I kinda reluctantly agree with the majority of everyone else...to just abide by her rules for now and bargain what you can meanwhile.
However, don't just assume you can't make it on your own. No, it wouldn't be easy, but it can be done. My brother dropped out at 8th grade and left home...yeah he struggled for nearly 10 years finding himself, but eventually got a degree in Chemistry w/honors on his own. I moved out when I was 19 making just over $7.00/hr and going to school. And my best friend couldn't stand his Dad/Stepmom and moved out when he was only 17 and a Junior in HS. You might have to resort to student loans, room-mates in low rent places, and cheap food. Thus you might find you essentially have a net loss in freedom comparatively, as you may not have excess gas money, free-time from work, etc. Yet it might just make you more focused and appreciate what you gain in the end that much more.

I'm just throwing that out there though. Really it doesn't sound like your situation is worth the trade-offs at this time. I'd say just bite the bullet my friend and respect (even if you don't understand) her mandates.