How can I get my mom to stop treating me like a child?

I am 18 years old now, but my mother keeps treating me like a 14 year old. She acts like I am irresponsible and can't do anything on my own. She gives me a bedtime, I'm not allowed on my own computer for a certain amount of time, and she gets mad at me for coming home at 11 after hanging out with friends when she herself gave me permission to be out that late. I'm always responsible, I obey everything she says, and I always let her where know where I am at all times. Despite all this, she still acts like I'm a problem child who never obeys her and isn't old enough to make his own decisions. I would love to move to get away from it all, but I'm not yet in a position where I can even afford it. I also have college tuition to worry about.I've tried reasoning with her, but she won't listen. She ignores everything I say. How can I convince her that I'm not a child and that she should stop suffocating me?