How do I Get My Mom to Stop Trying to Control My Life?

You sound very bright and mature for nineteen. It is good that you are goal oriented and a shame your mom doesn't support you but, I suspect it's more a fear of losing you than anything else. Is she a single mom? An empty nest is hard to deal with and if you and your sister have been the center of her life, you can see why she's trying to dissuade you from attending college or leaving home. Just follow through with your plans and she'll eventually adjust out of necessity. Good luck.