Job question?

well im 15 and i have my life planned after high school. Im self taught on alot of things. i can strip, tune, fix, and build engines and i want to open a garage so i can tune peoples engines with after market parts. i also know alot about computers and ive built me own. I was wondering if you need some special degree or bacholoers to do this. im saving money to buy a garage somewhere and open it up as a shop. can i do that? along with opening a custom computer shop without having some type of doo hickey in college? i dont wannt go to collage just to open a shop. i have a sister whos also got the same idea and is going to be with me when we do this (shes 24) and ive got a cousin whos in with the computer stuff, so will this all work out fine?