@thatkidalex11,
This situation is really complicated. First her problems are far beyond what you can do. You must realize that, and understand you are just a 5 month boyfriend. And i assume that you two are of the same age. The only thing you really can do is support her, and thats all. You can give her advice, but as long as you are on a relatioship with her you may get hurt. I assume she has many emotional problems, i mean, how many sexual partners she had had by age 17? Sexually used by age 17? Multiple exes? You was her crush since age 15?
She lives on a very toxic enviroment. That has a very stressfull emotional situation. It depends completely on her if she wants to get out of there, if she wants to grow, if she wants to became a better person. She will need a lot of strenght and support and maybe even pschycological help at some point.
If you realy want to endure. You should realize all this. Sooner or later she must live her familial enviroment, maybe threw college.
Just be careful. Do not have unprotected sex. Do not make things complicated with a pregnancy. Help her have good grades, stoke up her dreams. This path if you want to follow her will be difficult and has no guarantees.