You'd have to be either a damn good looking 35 year old, or have loads rohypnol, or money to get with a hot 19 year old. I'm guessing option 2 and 3 are off the table since you're a school teacher. So do you have abs, lots of hair and a handsome, young looking face?
If not. Forget it.
There is of course the school girl crush scenario. Where he moderately attractive, but the girl developed a crush on him while going through early teens. That kind of crush is so ingrained that she would find it sparked up again when confronted with him. Unless he is rocking a comb over or something.
I have had similar things happen to me too. Like knowing the daughter of a family friend when she is like 10 and I am like 16/17. You know them, you meet them, you don't think anything of it. Then years go by and this little 19 year old hottie jumps out of nowhere while you are in a pub/club, greets like she knows you. Then 15 seconds in you are like.... Nooooooooo...... double take.... Nooooooooooo. Has happened to me twice before. Unfortunately both times I had my GF/Fiance there at the time. Awkward introductions to follow.