I was stationed at Spangdahlem Air Base in Germany, courtesy of the United States Air Force. Back in my day the drinking age in Florida was 19 and once you got overseas the drinking age on base was 18. (Outside the base, the drinking age was when you were tall enough to belly up to the bar and say "Ein Bier, bitte!". Germans are not so particular about minimum drinking ages but penalties are extremely severe for DUI. Not to mention that if you got tagged for a DUI on base it was an automatic Article 15 (non-judicial punishment) and loss of on-base driving privileges for a year. That was for the first offense.)
So, it wasn't such a big deal coming of age back then, considering I was legal in several states at the time. (And ID checking was seldom enforced.) However, the guys in my squadron in the dorms 'tagged' me 21 times in the arm and then got me drunk to kill the pain!
Trust me, once a few years have passed and you can go to a supermarket and/or convenience store to buy beer without being carded, it'll be such a non-event that you'll be surprised!