My boyfriend is very immature, and it is starting to upset me, what should I do?

You are very justified in your reaction to his immaturity. He is not treating you like the lady you are. I would say the best thing for you to do is confront him about it and tell him that he is acting very rude and immature. Let him know that you are NOT one of the guys. You are a girl that deserves to be treated with respect and maturity. If he can't grow-up a little more than i would say to dump him and move on. Find yourself a real man.