I can not say that I have a completely similar experience, but I find this VERY relate-able

So that being said, there are a few BLUNT points that have to be said - that you have to "confront".

1) She has a very spotty past. You have to find out if she is PAST those behaviors. If she isn't - then you do not HAVE a relationship (sorry if this is too blunt).

2) Her judgement has to be questioned - has she grown past these really bad decisions or does her trait of making bad decisions a warning flag for life decisions (not even sexual - but LIFE decisions).

3) CAN you get past those mental images? This is a lot harder of a question than the seven words. You have to be honest if that would bother you and fester in your soul....

I wish you the best. With or without this girl - I sincerely wish you the best. But speaking as an impartial observer - this girl has 2 and 1/2 strikes against her. I would question YOUR judgement if you didn't have concerns. Big concerns.

Good luck