that's never fun. my best friend hid her "relationship" with her boyfriend from her parents for i think 5-6 months or so. eventually they did find out, but thank god they didnt freak. (her parents are verrrrry overprotective)
sometimes hiding it is the worst thing to do, though.
(like you, both her and her boyfriend were hiding it from their parents-- and they were 17 and 18) but both sets of parents ended up being okay with it.