Plain and simple:
1. The Economy sucks: Recent college grads have a very tough time finding jobs....what is another 4-6 months wait.
2. If you wait, before you know it you will have responsibilities, a job, possibly a spouse...things that tend not to be conducive for going on a long hiking adventure
3. You will always have that little "Could a, should a, would a" in the back of your mind if you did not do it...and you will regret not taking the chance once you get ol