It changed the year before or right around that time I got in the Military (June of 1985), you had to be the legal drinking age for that state you were stationed in. I was stationed over seas right after basic training. Alabama where I went to basic training was 19 years old and I was 18 at the time so no dice for me. Of course I might have had a drink or two but you didn't want to come back to the barracks drunk in basic training because you would end up reviewing for a second time every thing that you drank or ate that day.
In Germany basically we didn't have a drinking age off base and I don't think we had a minimum age on base in Germany or at least I don't remember there being one at Patch Barracks, or it was 19 which was the age that I was the day I signed in at my new unit.