So if I'm reading this right, you told her mom and then her mom beat her?? Sounds like this girl has a weak support channel all around. If her home life is so crappy that her parents would beat her over being beaten by a boyfriend, she probably has little to no self-confidence so being beaten and treated like crap is something she is used to and she'll continue to deal with unless someone intervenes. Do I think you should be in a relationship with her? No. Definitely not. Should you be a great friend to her and support her and try to get her some help? Absolutely. She doesn't need to move into another relationship right now because she's fifteen, sexually active and is okay with conceiving a child...she obviously doesn't know what love is or what it means to be fifteen. More than likely she is love with the idea of being in love and will take whoever is willing to love her because she doesn't get it at home. You don't need an intimate relationship with her because she has a lot of issues and thats not something you need on your plate at 17. What you need to do is sit her down and talk to her straight. Let her know that you suspect that her boyfriend is abusing her, about her mom and home life and tell her you want to get her some help. If she agrees then go to an adult you trust who won't hurt her. Maybe a teacher or counselor at school. If she doesn't agree don't force her into anything. Just reassure her that you're there, as a friend, and if she decides she wants help you'll be there for her. However, if these people are beating her severely or regularly, you should go to someone who can intervene. Thats just a call you're going to have to make. Just be strong for her, because that is what she needs most, someone who cares for her and will actually support her.