Well... basically it depends on what state/country you live in. Most states, what you did is Illegal... your pretty much screwed if she wanted to tell authorities on you... I would definitly be careful on that. I think that 18 and 16 isnt too bad, but I think it still is considered illegal.
You should wait a while you know? but since you already dipped the stick its already too late.
PS: Dont piss her off!