Change the drinking age to 18 or change the age to join the military to 21.

I am loathe to the fact that i can sign up to die for this country but I can not go drink an alcoholic beverage if i have the inclination. My proposal is simple change the drinking age to 18 or change the age at which you can join the armed forces to 21. Both options seem fair to me. It seems rather silly to me that we are considered adults able to make decisions for ourselves when it comes to serving the country and potentially dying, but not when it comes to what we consume which could only kill us if we it is misused.