Age DOES make a difference because of the conflict a developing male experiences between orders, training and conditioning against the maturation process.
You can know all the rules and ace a test, but the street is where it is all supposed to work correctly ... which is not to say it will always be the chapter you read.
I just paid a school tax and part of that tax was "occupation tax" . Ten bucks just for living and working in my township.
I've known my tax lady for a number of years and she asked, "Are you still working or anyone in your home working?"
I replied no, my wife is my wife and I'm retired.
She, with a pen, crossed through my ten dollar line and subtracted it from the total.
Right in the office!
And she didn't call Washington DC or the IRS for permission
Just acted like a thinking American ... said, "That ain't right ", and corrected it.
Y'don't learn that in tax school and you don't get a pair of balls with your diploma .... that comes from experience.
The shooter was 48 with 24 years on the force and trains the younger cops.
The officer who held his fire was younger but still had 11 years LE experience — probably early 30s.