You will have to take the AFOQT.
Everything you need to know, including the process, the required package, deadlines, and the
official people to contact for additional questions is available on the AFROTC page
here. The applicable
AFI is 36-2013.
I strongly suggest you read the AFI for yourself and understand it, including keeping an eye out for future changes. I found many on-base personnel (who should know better), unknowingly pass along outdated or superseded information that can quickly derail an application.
POC-ERP is another route, as-is just finishing your degree on AD and applying to directly to attend TFOT.
As
@kinnem mentioned, you will need command approval for this. Begin with your First Shirt, your direct supervisor, and your Base Education office.
Lastly, if you took an enlistment (or re-enlistment) bonus, selection to an officer accession course
almost always triggers a forfeiture of future payments, and may trigger a repayment of what you've received. If you have less than 4 years (active duty years, i.e. 365 days x 4) TIS, then I'd suggest timing your package to drop after you hit that milestone. O-1E pay is much higher than O-1, and the O-1E pay after 6 years TIS is MUCH higher (close to O-3)
Persistence pays off. If you don't get in this year, keep applying and working toward your degree in the meantime. Good luck!