I joined an ROTC program in my junior year as a contracted cadet and went active duty after graduating. One thing I would add to the commentary above is that you should go into every ROTC office that is operating on your campus and interview them. I walked into just one of the ROTC offices and left convinced that that was right one for me. Shop around. Also, you may want to look at Marine Corps programs. While they may not ROTC building on campus, they do offer a program that prepares you for their officer candidate school.
Because I walked into their offices so late in my college career, I was unable to apply for a tuition scholarship, but at least I had the cadet pay and a good paying job after college.