Real advice.
Weigh her maturity level. If she seems like the kinda girl who can hook up now and again not tell coworkers, Facebook, gossip friends, etc then yea she is legal fuck her in any hole she likes. If it her child like naiveté, air headed wonder, and dependence on you as a work mentor and guidance figure... Well does work have private restrooms? You will find yourself in them often taken care of yourself while she works the sales floor. (I assume that you work retail.)
Last. Can you lose the job/type of work and not care? Then yea fuck her in what ever hole she likes.