Should I quit being her boyfriend?

My girlfriend has been getting violent with me in the past several months. Often when we are walking she pins me to the floor and starts punching me in my face. I start bleeding around my entire face and it really burns. I once had to go to the hospital. Sometimes she grabs my hand and twists it in an uncomfortable position. That is actually just as bad as her beating me. My mother asks me why my face is bleeding so often and i tell her i run into poles to cover up for her. Even at class she kicks me in my leg really hard under the table! My teacher thinks i am disrupting the class because of my reaction. When we eat outside she sometimes smashes the food onto my face. The food may be expensive and she always gets my clothes filthy and i regret paying so much for it. She also trips me a lot and pushes me into walls. I talked to her previous boyfriends and they said she never beated them and all they said was she was so pretty. Should I tell her that we are through or keep up with this?