just to reiterate what the previous posters said...
graduating in < 3 years isn't reccommended.
Hopkins pre-med advising STRONGLY discourages graduating early, even if it's to do something interesting/important. they say "there's no substitute for 4 years of undergrad". rushing through undergrad will likely hurt your gpa, you're missing out on experiences, blah blah blah.
I'm actually doing the 3.5 year plan so that I can have it both ways. I'd suggest that to the OP or anyone else considering an early graduation. it gives you time off without having to take an entire year (and your parents would probably be grateful for the tuition money!).
I'm going to graduate next december, work in my lab for a few months, then spend a month or two abroad, probably doing charity work/traveling.
good luck!