If you can vote at 18 and serve your country at 17, should be able to drink, smoke, and serve in the House, Senate, or even President.
As I continue my journey into cranky oldmanhood, in some ways I wouldn't mind seeing the "adulthood" age changed to 25, especially having witnessed how young college kids vote with either their sex organs or whatever makes them one of the crowd. Especially at the local level, where they then, like locusts, move on.
If I were to use a version of the leftist argument: "Hey- the 2nd Amendment was about muskets. Things were different back then". Just like things were different back then in that people took on adult responsibilities often in their early teens. Nowadays a lot of people are still not adults into their late 20s.
Okay, I probably don't want that in real life, but in my "Get off my lawn!!!" musings, yes I do.