I remember making this same call last year to financial aid. When calling, ask to see if there is a person who handles all ROTC cadets. The office should know this, however, if it is a student working the phones, they might not. Then ask that person how it works for that school. We were told, "I usually get a list by the end of the summer." My daughter was a 3 year AD, so not worried about scholarship, worried about room and board waiver from the school for 3 year AD recipients. His response was, "I put a note in her file, after she passes the fitness test we will activate it, there will be no late fees so don't worry." Then I got off the phone and encouraged my daughter to go for a run. Then second semester she was to activate, we ended up still taking out students loans to be sure, once the scholarship payment was processed, they returned the loans. All of these things are questions to ask the financial aid counselor.
Ask the school, remember, you are not the first student they have handled with an ROTC scholarship.