As a mom I wouldn't approve of my child being sexually active at 19 (not that I have much control past 18 to do anything about it). However if you are going to be doing it anyway I would prefer you were doing it at home where I could make sure you had access to anything you might need to have safer sex. I would also be more upset if I found out you were sneaking and doing it behind my back rather than just telling me up front.