OMG, my cousin keeps talking about the past. Need help?

[Cherry]

I am an understanding person but my cousin is driving me crazy with talking about the past. She keeps talking about my prom and how she felt I should not have went without her. I mean this was well over 20 yrs ago. She keeps talking about the friends I had in high school and how I should have dumped them for her. It's weird and she have brought it up severely times in the last few months. Granted she is drunk a few times but there were times when she wasn't drunk. I have listen to her and told her that if I hurt her feelings when we were in high school that I was sorry. To be honest I have no idea what she is talking about. We went to the same high school but we had our own separate friends we hung around with. I am trying to figure out how to tell her in a friendly way to get over it and move on. What do you think I should say? She is in a very sensitive place right now