If this chick is slutty or real?

Alright guys, well i have a gf who is younger than me by a year difference. I'm currently a junior and she is a sophmore. The minute we started going out people were criticizing me for going out with this so called slut? We talked alot and we clicked real well. When i asked her about her previous relationships, she told me she regretted everyhting and she hates her past. So i said woe this chick made some mistakes but she might be sincere and at the time of those relationships, just you know, not perfect. The problem is she was crazy in love with one of my good friends. She would make signs for him and everything, copy his number, listen to the music he did and its like wow. Now that were going out she somewhat doing the same thing for me. And she is CRAZY IN LOVE with me. The catch is a bunch of people are telling me that she had with the guy she was crazy for way before we even knew each other. Its like everytime i see her its like im seeing my friend. So i asked her if it was true and she denies it with agression. As if what kind of question is that. Yet the evidence is just their and one of my good friends told me the same thing. I just feel disapointed. I just dont know if she's telling the truth or not????????