As a prior enlisted USAF (Guard) pilot I guess I should throw in my 2 cents. Although, it will be for posterity's sake, since you seemed to have made up your mind. NightVisionPen is correct in that enlisting to become a pilot makes the most since if you're a going the guard route. However, I don't believe it's the terminal illness that the others make it out to be. I can think of two prior-E dudes off the top of my head, that were from my wing, who went off to be AD USAF and Marine pilots. This is on top of the multitude of others who are now flying in the guard.
Yes, being a sweaty, deploying, and going TDY makes it a pain to finish school. But I think the rewards were worth it. I got to serve my country, travel the world, enjoy stellar education benefits, and do some pretty cool shit. Yes, once you become an officer you'll probably get to do all of what I just said, but while my contemporaries were partying in the dorms, I was getting hooted up in Tokyo, Hawaii, the Virgin Islands, Iceland, UK, Italy and on and on. And, if I had never became a pilot, I'd still be happy and proud with what I had done as an enlisted bubba.
All that being said, you're making the smart choice. There is no guarantee that enlisting will get you a pilot slot, AD or Guard. And the vast majority of the guys in my UPT class were non-prior ROTC. Although they too were not guaranteed UPT slots, and had to compete for it. But if you can fog a mirror, and your not a complete douche your chances won't be horrible.
I'll add one caveat; do your HOMEWORK (in life and in school). Making snap life decisions based on what some guys on an internet message board says is bad form. For all you know I could be a fat, middle aged WOW player, living in my moms basement, who found a neat picture of a Pave Hawk on flickr and decided to create a persona on AW.
Hopefully somewhere in my rambling, incoherent post you were able to glean an insight or two.