If you try the after-your-degree route into the AF then you are talking OTS.

ROTC is for when you are still in an undergraduate program. If you are a sophomore in college you are probably at the last possible point for selection. Run down to your nearest AFROTC detachment and take the AFOQT right now. If you are past your sophomore year then you are looking at OTS as a commissioning source.

As far as getting a commission (the first step before going to UPT), OTS is the most variable (thus the most flexible for the AF). That means that one year the AF may take a lot of OTS candidates and the next year they may take none - consider OTS as the "shock absorber" for the AF officer input stream.

Your first step should be to walk into the closest AFROTC Det around you. It may not be at your school, but there will be one close to you. There will be some very well-informed people in that Det who be able to help you determine how to fulfill your dream.

Good luck!