OP mentioned intel as a possible fallback should flying not work out, and I'd stress that PMPT's sentiment above applies to intel, too. Really consider why you're fixated on the Marine Corps and ask yourself whether the MOS you choose is aligned with your goals. As a 26xx you might end up at a Radio Bn and get to play in the mud, or you might end up at a Cryptologic Support Bn and work in an air-conditioned joint-service office with an Air Force boss, a civilian supervisor, Navy and Army coworkers who play Magic: The Gathering in the breakroom, etc. Individual experiences vary wildly compared to the relatively stable "Marine-ness" of, say, 03xx fields. (This is why my answer to "Oh, you were in the Marines?" often begins with, "Well, yes, but...").