I have serverd in the Air Force faithfully for 17 years here, with 3 to go until retirement. There is one thing I can give anyone thinking of coming in as solid, sound advice ... and if you never listened to me before, listen now.
GO TO COLLEGE FIRST! Get a degree, and come in as an officer. At least then, there will be more $$$ right off the bat, and the retirement pay is more than twice that what your average enlisted person makes.
Enlisted men and women (no matter the service) don't make diddly-squat. Don't believe me? Check out the Air Force (for example) pay chart. Note the officer pay below the enlisted folks (the lower the "number" the lower the rank). Check out the difference in monthly pay between an E-1 and an O-1.
http://www.airforce.com/careers/paychart/index.php
Questions? Read this post again.
Sometimes the best thing to say is nothing at all.