A Daughter's Question?

I'm 20. I've been fighting with my mom a lot - more than the usual arguments - mostly about my boyfriend. Here's the deal - I'm not supposed to date until I'm done with my career - that's about 28 so I won't get distracted. I've been doing fine in school nothings really changed. And she says rude things to me about how i'll get pregnant and ruin my life ( this one would make sense cuz it happens but she's taught me better than that! I know what to use etc etc) and stop whoring around. Also ,She's decided to pick a career for me Nurse or doctor - even though I might not enjoy it. I need advice in how to handle this. I don't know if I'm being immature for wanting to do the things I need to do. btw, I work, I pay my own credit card bill, and do my equal share of chores in the house. Also, I'm not allowed to sleep over anyones house ( I ask on occasion maybe 3 times per year and still a NO!) - I don't go out too late.I always come home at 10:30 pm unless I need to work late. So I need help to hand this situation with my mom. I love her but I feel a little bit smothered.