Ok there is a couple of routes you can go.
What part of Game Design and Development do you want to go into?
There is Game Art and Design, Sound Production, Programming, etc...
Secondly, In my opinion Tech schools are nice, but they will not give you a rounded education like a normal college will. It just depends on your style and expertise. Some people cannot handle a regular college. Sometimes I can't lol I hate sitting in classes that in the end don't really help me get closer to my career path but I do because it will help me get my degree.
No matter what, I would try to take Drawing classes and maybe some Calculus.
If you go Computer Science route
Any other type of Math or Science course will help you get into a college
If you go the Art Side
If you go the Sound side
Anything ... music
In the end I hope this helps