I think it should be based on IQ not age. The mental health thing is important but touchy.
You want to own a weapon? You must be nuts and not eligible to purchase one.
If people are going to judge no one will ever get a gun.
Psychologists/psychiatrists are overwhelmingly liberal, and their diagnoses are subjective. Half of shrinks are seeing their own shrink, while seeing their own patients. Crazy.
I get where you are going, but will say no to just IQ scores. Sociopaths often have high IQs and I dont want them to be considered favored in their decision making.