@Jeffrey1111,
Well, I'm sorry you feel this way. But I think you gotta recognize that dwelling on this is unproductive.
**** happens. We go through this, most of us, in our lives. Not everybody who we like will like us back. It can hurt, yes; I don't dispute that. But when it's a single-minded obsession (as this seems to be), then it's time to step back and get some perspective.
Whatever this girl's history is, so what? It should not matter to you. You need to take this experience and work to move beyond it, and speculating about whether she has ever had a boyfriend before is utterly counterproductive in that area.