Might be totally unrelated, but my first love was the "high school sl*t". She was well-known to have slept around, had sex with a dude I hung out with, she even got drunk and slept with his older friend on my birthday after she told me she'd be there (she didn't show up). She also cheated on me and slept with multiple other dudes while we were together, and I happen to be decently "well-endowed" and know how to use it (according to my past GF's and current GF). She even slept with my high school best friend on one drunken night which made my friendship with him awkward and we had an unfortunate falling out (we tried to recuperate it, but it was never the same after that dramatic, tear-filled night he broke the news to me). Despite the cheating that virtually everyone knew about, including me, I always took her back. Always. She was beautiful, got along with my parents, and I was in love with her. We did share a pretty deep connection and got along well, personality-wise, despite her being so promiscuous. We ended up breaking up in college. She ended up getting married less than a year later to a military dude -- when she always told me she didn't want to be with a man who was like her alcoholic and abusive military vet dad.

Basically, the moral of this story is that -- you're still young AF and have a lot of life lessons ahead of you. Do what feels right to you, in the moment, don't be afraid to make mistakes / heart-break, learn from things, and have no regrets. Everything happens for a reason.

If her past relationships bother you, then let it affect you in whatever way it does. Insecurity, whatever. You'll learn from these experiences eventually, at least, that's my hope. Good luck.