If you're not trusted enough to drink, you shouldn't be trusted enough to get married, and shouldn't be made to go to war. Whether that's 18 or 21, it should all be the same. You can't rent a car in America till 25. We need an agreed upon point of "adulthood". And we know that not everybody matures at the same rate, so that point should be debated, but it should all be the same. The brain isn't done developing till your early to mid 20's. I personally wouldn't call myself mature till I was 28 or so, and I had already been drinking, smoking weed and been sent to war by then.