It sounds to me like she has matured a lot. Getting sexually active at 13 is kind of sad. I think it says more about what happened to her, than what was done by her. Consider how she treats her child. Then look at how she treats the aunt and uncle. Then consider how she treats you. If those 3 things check out okay, then I wouldn't worry about her past. Something went wrong in her life, but she seems to have found a path out of that. Someone who has had to overcome a difficult start in life may be a very worthy person for you to be with.