The ‘drinking age’ should be 18. You’re either a legal adult at that age, or you’re not.
Having said that, I’ve often thought that the legal age to vote should be at least 30-35. One can do a hell of alot more damages to themselves and others at a ballot box than they can with a bottle of beer.
Or, before casting a ballot you have to take a short quiz on ‘civil intelligence’ - as in, Who is your Congressmen? Senators?..ect. Miss two questions, and you can still vote, but it isn’t counted. Could also apply a simpler test. One must net PAY taxes(not counting Social Security or Medicare contributions) before you can vote. When registering, you must show up with the previous year’s income tax forms, or from a year when taxes were net paid.
A practice banned by the Voting Rights Act of 1965
I’d change it to 22 instead of 21, gives them a chance to get out of college alive.