>and how to drink in moderation and avoid hangovers (to help them in social situations). Many people who start drinking early also don't learn those lessons.

Looking at drinking age 21 in the US vs drinking age 16 in Germany, I would say German college students don't put so much effort in getting wasted in my experience.

Starting earlier gives some time, where the kids are still somewhat under the control of their parents, to adapt to alcohol. At 21 I feel like a lot of Americans already have an unhealthy obsession with getting wasted, because they've waited so long to get there.

I do understand that in the US you get your driver's license at 16, and having these events coincide would be horrible, but it's not entirely clear cut to me whether this trade-off is good.