It's just objectively false. The minimum wage was not "meant for teenagers".

No business which depends for existence on paying less than living wages to its workers has any right to continue in this country... By living wages I mean more than a bare subsistence level - I mean the wages of decent living.

-Franklin D. Roosevelt

You can hem and haw all day and what minimum wage should be, but what it was meant to be is unambiguously clear.