I don't know how to feel, any tips?

So i've been dating this girl for a little over 2 months and so far so good. We've been having great days together as we meet basically every day.

I just sometimes overthink, Maybe it's just because I'm insecure or I'm anxious but I just can't stop thinking about her past...

She's had 3 exes before me and has had ___ with all of them. The thing is, the ex just before me only dated her for a week but they still did so much that i've never done with her and they broke up not so long before we met. I don't know but it makes me feel uneasy, she's my first time so maybe that's why I feel very anxious but I just feel like she selects boys a little less carefully as her ex is a really bad person. I've already spoken with her about it but it doesn't seem to help really... I understand if she has a high sex drive but I just can't help to think about them together...

I just feel a bit like a second choice you know? Like a backup incase the boy she did want to be with didn't work out because there's more but I just don't want to get into detail here.

I understand that I'm just 16 but I really love her and she's the only person I've felt comfortable with and I never spoke to girls before her so maybe it's because of that but I just wonder sometimes how she ever liked her ex... I don't know.

I hope I can get some girl and boy opinions on this.
Feel free to leave some comments below I'm active to talk more about this.
I don't know how to feel, any tips?
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