Her

I've been overthinking something and I don't know if I'm just being insecure or if my feelings are valid. My girlfriend gave me access to her account and even told me I could check it whenever I wanted. One day, I remembered the stories she told me about having a lot of past relationships. Curiosity got the better of me, so I scrolled through her old chats. I found conversations with some of her exes that were never deleted. I also found an old conversation with herself where she had saved pictures of her exes and other things related to them. I know these were from years ago, but seeing them still made my chest feel heavy. What bothered me even more was finding out that, years ago, she had cheated in a relationship before. I know people can change, and I don't want to judge someone only by their past. At the same time, I can't pretend that what I saw didn't affect the way I think. She hasn't given me a reason to doubt her in our relationship, but now I'm struggling with trust because of things that happened before we were together. Am I wrong for feeling this way? Is it fair to be worried about someone's past, or should I trust the person she is now?