I'm sorry but this is ridiculous. It doesn't make any sense to say that if you really love something than you should be willing to hurt yourself over it. You can practice releves and such at home after you know what your doing, but it is not safe to try and learn all by yourself at home. Yes, the girls can be annoying, but they are just something you deal with, and I have met some of my best friends in ballet class. They also give you much needed competition. I'm sorry, but in my (and everyone else's) oppinion, it is never okay to intentionally injure yourself. You owe it to yourself to get professionally trained. Home practice should be in addition to class work. There are many things (such as center, balace, foot placement, leg straightening, foot pointing, arm styling, head placement, creativity, turnout, toe stance, musicality etc.)that a book can never ever teach you. You will be someone that knows ballet exercises but you will never be a dancer.