I dont want to come across as judgmental.....but you asked ......so here goes.
I am 40,your age ,and work in a high school .I am surrounded by young men,16,17,18,19 years old.Im also the mother of a 21 year old daughter.
I can tell you that young men at that age(even at 19) are not emotionally ready for commitment and would find it difficult to stay in an intimate,mature,supportive relationship.
Chances are that his fancy for you is probably not for your intellectual side,if you know what I mean.You also take the chance for the community,including his friends casting you in a bad light.

Ultimately,if this young man consents and is of age.....you could go with your feelings and be with him.Just be prepared for the possible consequences.

Are you sure its worth it?

Good luck and best wishes.