[El Gato]

The corporal joined after 9/11, so he has been in only two years. But why he didn't try for OCS (too old?) when he had a degree

Yep, from Army Officer Candidate Page OCS requirements tab.

At least 19 and not older than 29 at time of USAREC Selelction Board. (age waivers will be considered on a case by case basis for applicnats ages 29-34)

If he's 36 now, he was 33 or 34 upon enlistment, depending on how long after 9-11 he enlisted. An age waiver might have been possible then, but now he's too old for even that.

[Blood of Tyrants]

Too bad. He looks to be excellent officer material.