What does it mean if I have been OML'd by the AMEDD for 66T?

It means you were selected by the board for commission, but there currently is not an open slot for that AOC. They put you on the order of merit list (kind of like a waiting list that is ranked by order of merit of who is most qualified). If more of that AOC opens up this fiscal year then they pull the next most qualified candidate off the list which may or may not be you. If they don’t need anymore of that AOC for the fiscal year then you sit on the list and then reboard again for the next fiscal year. It’s not fun. I’ve been there.

Now being a nurse you might have the option of switching to another AOC if you qualify and not waiting much longer for a commission or if 66T is what you really want then you’ll have to wait to see if they open more slots this year.

From what it sounds like, it sounds like you were put on an Order of Merit List for who gets to go to 66T course first.