I think it should be 18 again. Alcohol was never really a big deal in my house, in fact I can remember being 12 and allowed to drink a glass of coke with some red wine in it. It was completely normal to me and there was no mystery behind it when I was in my teens. I attended parties and drank before I was 21 but never did I drink to the point of incapacitation; I just never saw the point to it. I rarely drink anymore; and most likely when I do its a bottle a wine I share with my brother when he visits or at family functions.
It just never made sense to me that I could fight for my country and get married, but not have a glass of champagne to celebrate.