Yet another false dichotomy.
Not everyone is so clear cut on one or the other issue. For example, I’m not a fan of either premise.
There is also a difference between owning a gun and discharging the gun. People under 18 are certainly allowed to do so under their parent’s supervision. Once outside that supervision both the parent and child is liable.
Especially if the result of that lack of supervision ends in death.
As for gender assignment, not a huge fan of that either when it comes to pumping a child full of hormones of their desired gender. That should wait until they’re eighteen.
However, if boy wants to wear a skirt or a girl wants to wear pants; and they want people to use a certain gender pronouns around them then they can do that. Nor should be obligated to take the choice of a seven year old so seriously. That doesn’t mean the kid shouldn’t wear the clothes they want, so long as they follow the same rules as any child wearing those same clothes!
It’s really not that hard. Nor is everything so cut and dry. Let kids decide but only to a point. Parents should have the freedom of deciding that point. Not the child, nor society, and not anyone else.