Honestly I'm kinda OK with that.
A) the legal drinking age, age of consent, voting age, and age of Draft/ military eligibility should be the same. Whether that's 21 or 18 or whatever is up for debate, but if you're old enough to kill people at your country's behest you should be old enough to decide what goes in your body.
B) Lots of countries are pretty lax about kids drinking small amounts of alcohol, and it doesn't lead to increased negative outcomes.
Requires an act of congress and elimination of the filibuster. Not possible with the current makeup of the Senate. Need more blue senators, which is hard because California gets the same number of Senators as North Dakota, which has the same population as a small apartment complex in LA.
So we need record turnout for that. Vote.