Why does this question remind me of a recent movie?  I think the title was "Wild Things" and everybody dies in the end except for the teenage vixen who is behind all the seductions and manipulations.  It was a pretty good movie, but definitely a horror movie for teachers and vice-principals alike.

Look honey, your vice-principal can either be a good guy or a bad guy.  If he's a good guy, he will not have anything romantically to do with you until you're a safe 30 years old.  If he's a bad guy then your romantic interests might be returned which would probably put him in jail and leave your life changed in numerous unsavory ways.

There's nothing wrong with fantasies about older men.

She shouldn't even be having those fantasies.

There's a lot wrong with action.  At age 16 you should be developing your socialization skills with other teenagers who are testing the waters in new situations and relationships.  This is a part of maturation. 

Grow and mature and in 10 to 15 years, if you have still kept in contact with your vice-principal (without being a stalker), you might mention your feelings to him.  But I am pretty sure that by that time you'll be involved in other real relationships that neither party will be jailed for, and that you won't want to leave. 

To find out about the Mann Act, check this site.

Oh, and BTW, you might want to study up on the Mann Act.

Lefty