Look, Ma! I'm All Growed Up!

I really wish some people would give me more credit for my thought process. Some people seem to think that I can't be trusted to make my own adult decisions, simply because I'm younger than them. I firmly disagree. I am fully capable of making my own decisions, I know more than they give me credit for, and I do listen to advice, I just may decide I don't agree, but I'll have my reasons. I don't like being ordered around, and I don't like having to constantly justify myself to people. Especially people who really do matter to me.
Sometimes it seems like I don't care about people's opinions, when really it's that I'm tired of being treated like someone still in grade school, and I want to make my own decisions instead of doing whatever I'm told like a good, meek little girl with no thought process. (And no life, for that matter).
I just want to be me. Is that too much to ask?