My copycat bestfriend MIGHT go to the same high school as me next year?

As long as I known V she's always copied me in evrything I do, wear, act, say, evry single thing. I am NOT kidding. I know I should take this as a form of flattery, but it really isn't. It's like V is trying to steal my identity and trying to be better than me. She's always showing off & I feel like I have to compete with her. We never acknowledged this problem. We're in 8th grade & on Friday, we're going to get our high school results. Since V is always copying me, she just happened to choose the same high school as me for her first choice. I dunno why I told her, I believe it was before I was really bothered by her copying me. I don't want her following me in this. Reason being that, since I've always hung out with V, people have been drawn away from me. She's the Gothic kind of person, while I'm the happy perky person. And I cant avoid her becuz, the teachers sit us together. I want to branch out & have friends in high school, not be stuck with her. What should I do?