@Blackbird : I have raised 3, and now have grands. In my experience, boys mature slower than girls. They are much more prone to being less responsible. There ARE exceptions to that rule, I can only speak from my own kids. Right now, I have two that are 3 years apart. One will be 18 in July. He seems to jump before he thinks, then realize maybe he should have thought about things more. Other one just turned 15. He is pretty responsible, but still has teen "memory blanks," aka "I didn't think of that, or I forgot." Then we have a soon to be 12 year old boy. He puts himself to bed, manages his own wardrobe and clothing choices, and even fixes his own lunch.
Each child is different, Unfortunately, we can't design a new law/rule for each child. We can't even group them. It has to be blanket coverage. I would like to see having to pass a class, not just a test, but a class then a test for all new gun owners before purchase. This would not be an end all solution, but maybe a start.