I have to disagree with crunkologist. If you haven't done any training at all and only weigh 130 lbs, then I'm guessing that doing a few pushups is relatively difficult for you. It's a good start, and it's free, so you won't blow your money if you decide to give up.

That said, the gym is probably a better idea, but it's not like pushups will do NOTHING for you. That's just absurd.