Legal drinking age

I just got into a discussion with a friend of mine about the legal drinking age in this country. The US is the only country whose drinking age is 21+. I feel that this is ridiculous, considering the fact that by 18 we are considered to be legal and can do basically everything else, including being able to vote and being able to enlist in the army. Isn't it reasonable to say that if we are wise enough to choose the leaders of our nation that we can make wise decisions about drinking. Or what about the fact that we can go into the army and kill our enemies, but no, we can't order a drink at a bar. I feel that by passing such laws the government is contradicting themselves. If we have the chance to make such serious decisions, we can make decisions about drinking. If what the government is worried about is the accidents that may occur if they let 18 year olds drink, then they need to check the statistics and see that just as many legal age drinkers get into accidents, if not more. I feel that if the government allowed us to drink than we would be more responsible with this provilage and would not abuse it.