Gf has done more than me :( Need help to get over it?

Ok so me and my gf im 15 shes 13 so like we are deeply in love even if people say were too young to know what love is but im sure enough to bet my life on it, anyway we are planning to have next summer when we see each other since she moved (long distance) and she told me that shes been fingered twice by 2 different guys when she was like 12. that really ****** me up bad cause we promised to give each other our first for everything(cept kissing) nd i feel cheated by her. she let some guy she didnt like at all and who wasnt her bf touch her down there and enter her. same with second guy and the second time was outside behind a building. no one has ever seen her naked but me or touched her appearently which im not buying either i feel rlly disgusted and a bunch of other mixed feeling becuase at that young age she did it and im wondering if shes the same girl as now cause she has rlly changed from what she told me about her past self. i feel as if im just another guy sometimes and that when i do it to her it wont feel very special or enjoyable and i rlly wanted to be her first. sometimes i feel i dont even wanna touch her no more when i see her when i visit, how can i get over this...i feel so selfish at myself and feel like a brat but at 12!? comon shes wanted to have "fun" and she said it felt rlly good but her mind didnt like it. idk what to do i feel like a complete loser and it irritates the **** outta me when i remember shes gotten fingered, i wanna get this feeling outa my chest and want to move on, also i cant really talk to her about this cause itll just cause a fight and shes sensitive