You chose about the worst time possible to try and get in the sport.
Right now pretty much the only way to get guns right now would be to get age verified, which you can't do, and browse the classifieds.
Getting guns while being a minor will get you flamed.
You're best bet would be to though out the last year you have to wait and pile your money. You will need at least 600$ to buy the basic gear, 1000$ to have a decent setup, 1500$+ for the cool stuff.
Good luck, but wait.