You say this like the conclusion I’m supposed to draw is that it doesn’t matter that they died from firearms.
If you use 1-19, firearms are the leading cause of death, if you use 1-17 they are not. In almost every other context we consider 18-19 adults.
suddenly adult privledges, and expectations are now part of your life, and if you can make it past year one adulthood, this window is passed