With any ROTC program at colleges, please first find out if that college offers a ROTC program.
The university I attended, Villanova, has a long time established ROTC program with the NAVY.
The schools will give you the requirements needed to join the program, and the benefits associated. Normally, the military service will require 4/5 years of active duty service once you graduate college and are commissioned an Officer.
Each branch has its own ROTC program and some campuses may not have all of the branches represented. ROTC programs offer scholarships to qualified individuals on a competitive basis, but starting in an ROTC program is as easy as taking one of the ROTC classes at your college. Classes like Military Science will automatically get you enrolled in the ROTC program without committing you to military service (you can try it out and if you don't like it, you can quit).
There are requirements that must be met and the differ for each branch of service. You should talk to your high school guidance counselor as a first step to find out if the college that your interested in has an Air Force ROTC program.
Lance recommends the following next steps:
Lindsey recommends the following next steps: