I don't regret for one minute that I enlisted first. But at the same time, all of my (non-prior) compadres are starting there flying careers 4-5 years younger than I am.
If I would have attempted college right after high school, I more than likely would have failed out and would still be working on a ranch for $50 a day. I credit the USMC for giving me the decipline and determination I needed to get through college (not to mention the funds). Keep in mind this is ME, lots of people do it right out of high school. I'm not trying to talk you into enlisting, if you think you can handle college right now both financially and academically, then go for it.
If you go Active duty enlisted, then you can pretty much bet on serving your 4 years before getting picked up for OCS. I found out that I had a better chance of doing my 4 and getting out and going PLC. It's not impossible, just very competitive. Crowbar has a lot more knowledge on this subject being that he is currently in one of these programs.
There's no "wrong" answer, you just have to find out what route works for you.
Good luck!
Beetle