You had "STOP!!!" at the "24 year old guy" part. The seven year difference in ages is way more important than the difference between a 23 year old and a 30 year old. WAY more important.
I would not allow any child ov mine, male or female, to date someone that much older than them. Even if I trusted them as if they were saints on earth, I would not allow it.
As for a teacher dating a student... That's not only asking for being fired AND run out of town on a rail, it's asking for someone to come after you with a shotgun. STOOPIDDDD! And illegal as all get out too, no matter what the local laws about age of consent are; there's an issue of sexual harassment here. Since the guy's a teacher, he's in a position to "favor" the girl, which makes anything between them tainted by the possibility of duress on the girl.