Is it possible to commission in the AF with an RE3 O code?

I don't see an RE3 O on the list. What is the characterization they are telling you ?

I would probably run it up the chain of command to see if you are getting erroneously penalized for not accepting a job that forces you past your ETS. There is no stop loss and they should not compel you to stay in for reasons out of your control. I would even go as far as a congressional complaint, it sounds like they are penalizing you for something that they shouldn't as retribution. I would go through that route first. If you have only a year left of service, its unreasonable to say you have to select a duty that will push you past your ETS. If it turns out this is standard procedure in regulation, you might see if your leadership will be willing to write you a letter explaining that not opting to extend your enlistment for reasons that go against your personal growth plans, forces a reentry code, might help in a waiver process. At least there will be a record on specifically why you were given it. Without that documentation, its hard to say how a board would look at it. If I was on a board and saw no justification, human nature is to assume the worst case scenario.

You will want to google Air Force Officer accessions recruiter. I think they only have so many that service a wide geographic area. Not all of the recruiters are officer recruiters, since it involves a completely different process of putting officer candidate packages together for OTS.

I did pretty much the same thing. Signed dec statement for recruiting duty, RE3 code. Got out. Went into reserves, finished my education, applied for commission in the reserves, then transfered over to active duty b