What should I do about this?

Ok this might be long so please just hang in there. So I've been dating this guy for almost a year and a half now I'm even going to his prom in 2 weeks but my mom just dropped a bomb shell on me. She doesn't like him. She says that he doesn't understand what a catch I am and that he is cheap, domineering, forceful(possible dangerously so), and just doesn't appreciate me. Now I know a lot of girls my age(I'm 15 my boyfriend is 18) wouldn't pay to much mind to this but my mom's opinion means a lot to me and I am unsure how I feel about her not liking my boyfriend. He is always loving and affectionate to me and he always makes me feel beautiful but my mom has a point with a few things. The thing that set her off on the rant in the first place is that he refused to pay for my prom ticket(it was $80 and he goes for free) and we get into fights that i honestly don't understand why we're fighting. The most recent example of this is when I told him that since he's going off to college soon he should go see this movie with his mom that they both wanted to see but he wanted to go with me. I knew it would mean a lot to her to have some "last minute" bonding time but he just keep telling me, "She'll be fine. I want to hang out with you." So anyway I guess my questions are: is my mom right? (please don't start on the "you're-too-young-to-know-what-love-is" thing)?