As a 'rated' cadet you are ineligible for an educational delay, however you are eligible for an administrative delay.
I think the reg you are looking for is AFOATSI 36-2018. Check for the current version, I haven't looked at this for a year or so.....
The memo is very easy, will take you no longer than 6-9 minutes to make. HQ approved my request within 48 hours, new EAD and class information within the week.
IMO you should be accepted into grad school by the time you submit your request. I was accepted, had an advisor, research project, graduate school approved academic plan (basically a Form 48 for big kids), and funding squared away before I made my request. HQ is more likely to approve your delay if you have all of your ducks in a row.
Remember you only have a year to complete a two-year program. Be prepared for a fire hose.