ADVICE NEEDED?

My mum has never really let me do much with friends, at first I thought it was overprotectiveness but now i'm 18 and I dot know how going to a friends house afterschool is dangerous for me. The first time I went to a party (or a friends house in general) I was 15 and to this day she still doesn't let me out after half eleven and my dad has to bring me there and back. my sisters were always trusted a lot more than me, but one it messed up
The thing is that any time I try to tell my mum how I feel she literally will look the other way and ignore my existence, I hate it and it makes me feel so insignificant and like she literally couldn't care less about me, but she doesn't get it at all, even when I get frustrated or shout to get her to look at me she either continues to ignore me until I leave or she'll grab me by the arm and push me out of the room and lock the door or she'll start screaming at me, when my dad tries to get her to stop they get in an argument and I end up with the blame.
I know im 18 and people say I should just do what I want, no one can control me but it doesn't feel like that at all, it feels like im just a kid and I don't know what to do cause I don't want to hurt my mum or dad by leaving and I wouldn't have the money if I tried since i'm still in school, I just don't know what I can do to get her to understand how trapped I feel, I have only seen my best friend twice in the past year, and I find it hard to make friends that I cant stand losing anymore