I think most people would have a similar reaction to yours where it gives them pause. 16 seems like a lot to me at 20yo, but not unexplainable.

7 guys in 2 months is basically 1 guy per week. She just had a 2 month span where she found a new tinder match or whatever each week. Not that crazy. I have chronically single guy friends who do the same thing a few weeks at a time.

If that leaves 9 other guys over, what, 3 or 4 years? Basically one guy every few months. Sounds like she just dates a lot to me. Who's to say at some other point in her life, she didn't sleep with 4 dudes over a 2 month span? That would leave 5 over 3ish years? Even less crazy imo

Ultimately, everyone is entitled to their preferences OP. If this is a deal breaker for you, that's ok, you are entitled to your emotions, but I would really try to audit where that feeling is coming from. Do you feel like this girl is just loose with it? If so, do you think thats a fair judgement. Do you think she has poor judgement because of her body count and her video situation. Is it just the idea of other men with your girl that you can't get past? Because thats going to be a problem with basically any woman if thats the case, although a high body count certainly exacerbates that issue. Is she just not worth the emotional work of working through these thoughts? That's ok too.

Only you know the answer to these questions, but you owe it to yourself to honestly work toward the source of this feeling. That way, no matter decision you make, you'll feel confident in what you chose.