I don`t think that you should do whatever she wants, especially when you`re right. I`ve got a sister and we fight every day because there is always such a little silly problem. Don`t worry- different musical preferences are not something that you can call problem.

i gotz a sis n we fight bout lil fings 2, try headphones den she cnt turn it off or u can jus turn da music up 2 bug her

Smack her against the head. No, don't do that.
You can do whatever you want. You can like anything you like. See personally if my sister kept turning my music off I would go into her room, break her CDs, break her radio and fuck up her room. She can't tell you want to listen to. When you decide to put a CD in turn it up super loud and yell. I would.

Your sister has no right to do any of that. It's your music. I'm sure she wouldn't appreciate it if you did that everytime she listened to her music. Listen to what you want and tell her to screw off.

she cant do that to you. my older sisters have always been mean to me but my brother (who is my twin) and me get on great and hardly ever fight and like all the same stuff

maybe tell your mum that she is being so mean and have a family conferense about it?