I had a similar problem in High School, and I found that the best way to help yourself before you can get out is to find someone to talk to. For me, it was my step-dad, seeing as he understood what I was going through. Try finding an older family member that you have a good relationship with to talk about this with. It helps greatly with the stress. Also, simply proving that, no, she doesn't have complete control over your life can go a long way. Personally, I simply got an earring, but every situation is different. If there's something you want that your parent/s are completely against, give them some time to reason, but don't back down. Every little victory can sometimes prove your independence.
Hope it helped.
Hope it helped.