Re: Starfleet non-coms
In TOS, I always assumed McCoy was about 10 years older than Kirk (though Urban-Pine suggests less), and got his rank based on his existing medical degrees and experience. Don't current service organizations grant automatic officer ranks to enlisting specialists like medical personnel?
Curly: Moe, Larry, the cheese! Moe, Larry, the cheese! (Horses Collars, 1935)