Just to state the obvious there are three ways for you to move forward:
- Have someone you trust start the business. Have an agreement with them that they will transfer ownership to you when you are legal. By trust I mean -- like family trust. Not like the guy who is nice to you at the local Radio Shack. Sure there are lots of stories about parents screwing over their kids business -- but they are usually "entertainment business" where the kid was a movie star.
Wait until you are legal. That would suck. I bet your game is ready and hot now -- and delay is not worth it.
Wing it in the underground. Launch it on the DL, take money, sell your software, assume that you wont hit it big until you are of age and can convert then. Of if you do, you will have enough money to ensure the taxes and other obligations get paid. Think: "the newspaper route" rather than "the new Sony"
In most states in the US kids can run microbusinesses (babysitting, dogwalking, dandelion pulling) of a sort up to a certain amount of income and just show it on their parents tax forms. Might want to see if you can do that there.
If you image yourself pulling in more than pocket change before you hit 18 -- then for obvious reasons, I would go with #1 if I were you.