I don't screw around with girls under 25, they are just too dumb and boring, in general. But that's not to say there are not hot 18 year olds that a one night stand could be great.
All you dads out there need to realize your daughter is getting and going to be fucked more than you will ever know and you ought to be cool with it, not the jacka** the media tells you to be - and they probably started at 14 or 15.
IMHO cottage cliques are just a bunch of gossipy hypocrites anyway. If its not a about who fucked who, its about whose having marital problems or who has cancer or whose not talking to who and other such mundane crap.
I don't see anything wrong with what the OP did, if they want to skewer you, well drop them all, and move on.
Regarding FC's line above - bring your daughters - well FC, thats completely not the case with the OP.