By the time Germans turn 18 (legal age for stronger alcoholic beverages) most of them already know their limit and party with more responsibility in my opinion.
Unfortunately alcoholism problems are worse here in Germany than the US. Many point to the early drinking ages for this, personally I see it is more a general cultural issue.
I have no data to back this up, but I seem to find that regions at Northern latitudes tend to have higher rates of alcoholism. I think it has something to do with long winter nights and people being able to find a sense of community in a pub/bar/Ratskeller after the sun goes down at 16:00 for half the year.
The US is much further south than most of Europe AND there are large regions that are very anti-alcohol due to religious reasons.
You could probably back this up by looking at the alcoholism rates in Scandinavia (especially Norway and Sweden)
Scandinavia had their own prohibition and still to this day have a strict 18/21+ drinking age with booze only being sold during very specific hours (and never on Sundays or religious holidays), with anything above I think 12% only available at the government run bottle shop
I would assume there is good data to back it up as depression rates tend to trend in this way way as well. With that said, alcoholism in Germany is still worse than with US states at the same light levels. Also if you take a peek at lists of alcoholism Lists of alcoholism there are both dark and sunny countries in favorable and unfavorable places. So I'm not sure it can be a sole factor in drinking rates but likely a contributing factor.
At least most of me and my friends did. We still drink, but way way way way less. I feel like 21 or around there we the time we hit that responsibility.