So... now what???  

First, take a deep breath.
Then think about the steps it would take to become some variety of interior designer. How urgently do you need to make the change? Is the school thing a real or a perceived issue? Your marketing skill will help a lot. And, trust me, at 45, you're just a kid.

light-based detection chemistries and color expertise... Pt. 1
plus a love of interior design.
Hmmm. First joint on the decision tree is: decide if you're willing to move. Decide that without considering outcomes. Just decide where your heart wants you to be. Decide on luogo, as Sottsass says, i.e., place. Then figure out how to make a living in that place. Or alternatively, decide if place does not matter, or is only a raw material for what you want to do.
Some path suggestions...
A: Make artifacts for interior and exterior spaces that contribute dynamic coloration based on sensing of ambient light. Or make the materials designers need to make the dynamically colored artifacts. Inventor Path.
B. Get an undergrad degree in interior design online if necessary; then practice. Professional Path--Deliberate.
C. Practice without a degree. Just do it. Professional Path-Sudden. Some people can do some things and education only adds certification. If you can design people's interiors so exceptionally that they want to pay you, skip school. You can always go to school if you fail.
D. Get a list of the 100 most successful franchises. Supply your community with something off that list that it lacks. Entrepreneurial Path--Riding coat tails.
E. Start a concrete tub and hot tub business, because you obviously love them. Entrepreneurial Path--Passion Based.
F. Examine what your father did for a living. Pick something very close to it and do it. If you've already done that, pick something new as far from it as you can and do that. If you've tried both, do exactly what he did and envelope him. If you've tried all three, recognize you can let go of him, feel the unbearable lightness of being, and float into whatever comes up and start a new, unfettered progression. Serendipity Path--Parent Myth Driven.
G. Volunteer in the most lowly kind of work you can think of (or volunteer in a monastic order for a time) and let the awesome reality of the world overwhelm your defenses and need to control and then make a job hunt based on that new undefended awareness of what is needed. Pause, Reorder Awareness and Job Hunt Path.
H. Ask Koen for a job, any job. Offer to work for free if necessary. Mentor Path.

light-based detection chemistries and color expertise... Pt. 2
The most important advice I can give you is decide what you want to do and start doing it. But make sure its something people want. This is easier than it seems. Just think practically. People like tools and gadgets. Therefore people are needed to design them. People like homes to live in. Therefore, people are needed to make them. People like water and being clean. So people are needed to make bath tubs. Don't waste time trying to become a professional at something people don't like. Most people may wish they were organized, but they really don't like being organized. Hence, your business only fit with half the nature of people--the wish side, but not the like side. And the people who do wish and like to be organized are so compulsive and orderly and controlling that they not only can organize themselves, but they can organize everyone around them. No doubt a few professional organizers can make a living. There is a margin of everything. Just look at the working designers in the DA index. Look at their work. They design things people wish for and like. The things are mostly mundane and only made special by the "design." You must put yourself in a position to make the most mundane things that people wish for and like and design them in a wonderful, pleasing, useful way that is incrementally better than the last generation of that thing. That is all. And that is everything. It is that simple.
Walk through the same door to be a designer that the other designers did. Give yourself permission to design the mundane things people wish for and like.
A 52 year old friend of mine who has struggled his whole life to do something with his life successfully finally concluded that his problem was that he always said no to things before people told him no. He has spent the last seven years saying yes to whatever he wanted to do and putting the burden of saying no to what he wanted to do on others. He says he has found that mostly they still say no, but that now when they every once in awhile say yes, he does what he wants very well. And as time passes, he says, he keeps connecting up with more people who like to say yes and the more of those people he tries to work with the more often they do things as a group that he wants to do individually, too. he wanted to be a screen writer for 30 years.

light-based detection chemistries and color expertise... Pt. 3
At 52, he and a director are shooting his first movie. He said he had to say yes alot of times before he could find someone else who would say yes back to him. He said it was quite alot like finding his mate. You have to sift quite a bit. You have to hear no quite a bit. But most importantly you have to keep saying yes to yourself to having any chance to hear yes from someone else.
Do not view your professional organizing business as a failure. View it as a yes that heard a no.
James Joyce ended one of the greatest novels of all time, Ulysses, with a woman mythically joined with the River Liffy in Dublin saying yes I will yes.
I am inclined to think that Joyce and my friend are on to something and that they are trying to share it with those who want to stay alive all the days of their lives.
P.S.: Don't forget your connection to light and color. All people wish for and like light and color. The early work you did with it was framed and contained within a highly rationalized science. Perhaps you are finally ready to work with it in a more intimate, human way in a living space.

Seeing the light...
Thanks Geo. H. and DCW, both of you give food for thought, DCW in your usual intensive and insightful way you pretty much tracked all of the different paths I've gone down.
My Dad, husband, and best friends are all either engineers or architects and musicians or music-lovers. So the parent-myth path is one I've already traveled. My Dad is solely responsible for my love of wood, building things with my hands, music and logical order. My mother is lucky if she can find a pencil to draw badly with and thinks Neil Diamond is good music **involuntary spasmodic twitch**. Somehow I can't see myself in a monastery, I don't think they let women in for starters and my spiritual leanings are more in my head than on my knees. But letting go of my preconceived ideas of where I should be in life has been a journey I've been on during all this. As for school, personally I am a terrrible student in conventional circumstances. I excel when I am engaged, but do poorly when I am bored or annoyed by blaise instruction. (I plod badly and suffer fools ungladly) I can't afford it either; neither the time nor the cost. I'd love to work for Koen, but although we are located relatively close to each other in planetary terms, it's still a heck of a commute. And my only attempt at pottery in high school looked more like a fungi than a container!
I think that Path-C is my most likely course. Color is the most likely approach in doing that. Koen replied to this thread off-line and he agrees as well. He also suggested the Color Marketing Group as an avenue to approach. Do you have any actual jobs your fertile mind can imagine that are color-based?

I have a tendency to give my best shot the first time...
Hence, I could never have acted for Stanley "many takes" Kubrick, even if I had an acting talent. 🙂
As a result I am not sure I can come up with much more food for thought, but if I do, I will communicate it immediately as I know time is always of the essense in such matters.
Regarding the monastic detour, don't forget Yentl. 🙂

Well, now I've got it
After several months of hemming and hawing and searching around. I have found the next step. I have accepted a position with a renewable energy company that sells solar, wind and hdroelectgric power equipment designed for the home-user to install. I seems like a good option for me, career change into something that I feel strongly about and good potential for market growth. The salary is a pittance, but one must start somewhere.

Moi aussi
Hey O! me too. At 50 I realized I was unhappy with the work I was doing cause I just didn't like doing it any more. Computer animation, web game programming and interface design sounds like a field people are scrambling to get into but I've been doing it freelance for 20 years and I'm tired of it. I want to do something real. Don't get me wrong, I adore technology. I'm on the waiting list for an Apple iphone, but I don't want to make the stuff anymore ... currently on a sort of home improvement sabbatical.

Sounds
good, Olive. . . I think many could profit by recognizing the "coming thing." There's no time like the present to seize the future. All best wishes. . .
SDR

so now what
i am 56 started a new company three years ago and it has become wildly successful.
I am a little different from the average bear since i am somewhat wealthy from a previous business that is still very succesful.. and do not have to wonder if there will be milk on the table for breakfest,
i love design and architectue I started a company called retro redo three years ago cause i have one of the biggest collections of mid-century furniture and could find no one to recover all the furniture that i was buying on ebay, estate sales, and auctions,
I started with the shell chairs i went to 10 people and they all said No way i could do that , after i found someone I started putting together a website and advertising in magazines one thing led to another and a lot of free publicy amd testimonals from happy customers ... that little business
was off and running ,
what i am trying to bring out no matter what it is if it makes you happy low tech or high tech or what ever go for your dreams . My dreams were not to be a reuploster
but I have a been a business man since i was 26 years and have been successfull in my first business i knew i would be successful what ever i did . cause you never give up. I love design and talking to people so this business works for me and makes two people happy .

So, Olive...
What's up with the new job?