krav does this lady have a fiscus tree?
is the age the main thing keeping you from doing it or is it cause you kinda work together?
13 years younger then me is jail bait and even if it was legal it's way too young for me, but if she is 20 then she is old enough to make decisions.
over all i say go for it, but be a gentleman. you might end up having alot in common or maybe just end up as friends. either way having someone to hang out with after work is better then sitting home alone