Is it ok to be upset because of...?

You are not a pervert, just a natural 16 year old guy. I think she is just trying to bait you and make you jealous by telling you "what you missed." This girl is kind of a ho bag, not because she plays around, but because she flaunts it to you after the fact. She probably does this with other guys, too. Just to show off how cute or y she is or thinks she is. NOT COOL. Leave her alone and get a really cool girl.