(begin threadjack) Hey lthackston how's it going? Heard about the bad news for you SNAs. I'm sure most of the 18ers will do fine keeping the average needed, including you of course. There are a couple of people that might struggle though. I'm up here at Ft. Meade with the other 5 Cryppies that came here. (end threadjack)
Reservists who are seeking a reserve commission to remain a Drilling Reservist (SELRES) would go through a Reserve Recruiter (see your local ResCen). They do not attend 13 weeks of OCS, but rather 2 weeks of OIS (Officer Indoc School). Don't know which designators they are looking for, but I know most communities have as much, if not more than active duty officer programs according to the recruiter I spoke with a few weeks ago.
Reservists seeking an Active Duty commission would go to OCS just like civilians or prior service personnel.