c'mon you've gotta know its wrong. You're 13 and i don't know how old he is but i'm assuming at least twice your age. I think you have to accept as hard as this may be that he is disturbed and using you. It is illogical for an emotionally and mentally fuctional 30 yr old to be interested in going out with a 13 year old. This is extremely worrying and you should end the relationship immediately.
Did miss something. Where does it say that this person is a 13 year old and he is 30. Might be that the assistant is 28 and the student 17. In that case it would be okay in anoyher year. But right now NO! as long as he is in authority over her his butt van get in trouble! And, if she is doing anything with him she will probably go to Prom knocked up!