Yeah, mostly good ideas. I live alone, and have over 220 acres. I have plenty of room for target shooting. So I normally lock up the guns except a couple shotguns and my everyday carry handguns.
As far as guns in public, even though it isn't required in my state, I hold a concealed carry permit. I helped my kids and grandkids get their training and permits.
12 years old is a good time to start gun safety training. I actually was given my first gun at 8 years old. I never allowed my kids to have a gun without supervision until they were 16. At 16 in my state they can hunt small game alone. At the same time, 18 is the age they could carry a weapon concealed in public.
Nobody in my family, or anyone I know actually, has ever had an accident.
Outside of military service, the only time I shot anyone was in self defense. That person was on my property at 2am, and pointed a weapon at me. I didn't kill them, but it was dark and my shot went in the shoulder instead of the brain. Lucky for them my sks wasn't loaded with hollow points that night.
Knocked them down, and I stopped the bleeding for the 90 minutes or so it took the sheriff to arrive.
I think you need to adjust your city slicker attitudes to allow different rules when you live like I do.