I've never been skinny either... my lowest adult weight was around 165lbs, and though i've gotten there twice, it seems to be the barrier that i can't break!!
i can seriously not imagine myself weighing 140lbs or 130lbs... though i sure think it would be great!
also, it makes me kinda sad that there are some people on this thread who think that they're "fat" or consider that they have never been "skinny" (i think the OP just meant "thin", not a size 0...) even though they weigh even less than i do
and i'm not even the biggest girl here. just remember there are people here who would kill to be as "fat" as you are, eh?