At what age indeed
Well, where I grew up in Canada, it was 19 but of course, I drank alcohol for the first time when I was 11 and then again when I was 15, so had the legal drinking age been set to 21 or 30 I'm sure I would have gotten my hands on it by that time. At the time it really bothered me that I had to pay taxes, could vote in an election, and get married legally without the consent of an adult before I was able to drink alcohol as an adult, but what did I really know? I know now I shouldn't have gotten married at the age of 18, so it just tells me I knew nothing then. Likely my decision to consume alcohol was also driven by the curiosity of my innocent mind and desire to experience something forbidden.
I'm really not sure how alcohol can be used responsibly by adults or children, I don't know. I question the whole notion, because of the direct physical sensations that are felt from immediate consumption.
This question is pretty touchy. You've got balls for polling it.