Not allwed to be a 15 year old please help :(?

Unfortunately, it's not a 'liberty," it's a privilege until you're 18. When I was 10, my mother pressed "ungovernable charges" on me, resulting in my being put on probation for a year. The probation officer made it clear that all your parents have to do for you, by law, is provide you with at least two changes of clothes, three meals a day (or the food for you to make those meals yourself... and a "meal" can be a hotdog), and shelter. Your stepmother is taking advantage of the fact that there is nothing you can legally do about her crap, and as someone else suggested, doesn't want you to be happy because you're not her daughter. You've only got 3 more years, though. Just deal with it until then, and concentrate on your schoolwork. That is what will get you the hell away from her - go to college!