Think about it, if you were a 160+ years old, had seen the world over and over how comfortable would you be sitting in a high school class with a bunch of dumb twitters? That's my biggest issue with the show. It could have been solved by aging the female character a year, as an 18 year old senior dating a supposedly 19 or 20 year old guy would not be that unheard of. I can think of nothing dreary or more tiresome than sitting in a class all day listening to some idiot drone on about facts when you have lived that history. Stefan needed a better cover story.
I consider the show light diversion, a bit of fun, but as with all Williamson shows it seems that anyone over 20 does not exist in the town.