I used to be a pervert in high school
What would make you a pervert?
I liked to watch nude videos in high school
This sounds like something that most high school students have done which isn't really that bad! As long as you didn't let it turn into real life creepiness then there's nothing wrong with watching some bad movies.
I swear it's fine. Don't be such a prude.
You're right that there's not really anything with watching movies like that as an adult and I empathize with you. The things that we do as high school students rarely has an effect on how we turn out, anyways.