Seventeen is very young and very dumb. 25 from my vantage point isnt much better, but really 17 and her teacher? Maybe some people are mature at 17 but I sure wasnt. That's why so many kids get pregnant from prom. Dont they? Maybe she liked feeling wanted, feeling favored. That's what it would have been about for me. You sound like you're looking at it from a guy's point of view, which is natural, but gives a weird answer. It's probably different for a girl.