Is it normal for a 13 year old boy to be atracted to his teacher?

I noticed my son staring at his teacher and after a long discussion I think I taught him not to stare. I was wondering is it normal for him to be attracted to his teacher because I wasn't even attracted to women until I was 15 and didn't date until the day after my 16th birthday. Although I was never attracted to my teachers to me they were just educators(aka the enemy).