AIO to finding a video of someone doing coke off my new girlfriend’s titties?

I 24m got together with this girl 27f about 9 months ago. Everything has been awesome she seems like a really good person we connect on a lot of different levels we talked about drugs and i expressed my emotions that I don’t like drugs other than weed and shrooms. I come from a family where drugs were very prevalent my mom and dad were addicted to meth when I was very young they are finally clean and sober now. My brother unfortunately started doing cocaine then went to meth. I expressed my feelings towards this and she said I had nothing to worry about. She said her friends have done cocaine around her but it’s not her thing because she too has family that are addicts. I thought everything was cool because I too have friends that dabble in cocaine but yesterday I found a video in her phone when we weren’t together of some guy doing coke off of her tits. In the moment I was very upset because she’s told me yes they did cocaine around her but she’d told me that it was in other rooms and that she doesn’t like it. I then found this video and all of my thoughts of who she was is false. How can I trust her that she too didn’t dabble in cocaine use? I’ve never tried cocaine so I have no experience with this sort of thing. I’m honestly too scared to try it because I’ve seen what it does to my friends and family. Am I over reacting about finding this video. I feel like it’s in her past what ever she wasn’t with me but then another thing that goes through my mind is that she’s done cocaine and other drugs that I am not okay with. I know everyone has experiences with drugs and stuff in their early 20s but it’s just never been a thing for me. Thanks.