I strongly encourage you to get into doing your own thing and building something. It's something that I really wish I had done when I was your age. That said, you have to understand the sheer amount of work involved. Making a game is much harder than making a website or even a normal mobile app. Making a game is hard because it requires a story, design, gameplay, backend (for save games, user accounts, etc), art, sound and marketing
. It's very hard to get all of these things done on your own, and even harder to get them right your first time around. That's why it's great to start now, but understand that you will fail
at one or more of these things. The key is to not get discouraged by failure
and understand that by trying and failing, you'll learn more than you ever would from any class or course.
Good luck, and I really do hope you go through with this
. I might suggest teaming up with other people your age that are interested in making games. Don't worry about the LLC/business stuff for now, try making the game first and you can worry about that later