I think he asked for a translation, not advice on how to live his life... but I might be mistaken

Let him find out for himself what to say and what not to say

Anyway, if it is a girl in class, don't you think you'd use the more familiar term ты? It's not like they are perfect strangers and they are the same age. I say yes!

Therefore:

ты - единственная девственница, которую я до сих пор встретил.

Мне очень приятно быть с тобой знакомым.