My youngest is 8 and 10 years younger. He grew up in their world. His 5th birthday he told his mom who he wanted to come to his birthday and they were all 13-15 year olds. Not a single kid his age because he wanted to play ball. He was swinging a metal bat at 18 months hitting a pitched real baseball. His brothers and their friends took little off him. When he was 6, I was announcing a game and looked down in the bullpen of the varsity game. He had snuck in there, fit through the hole in the fence, and was warming up the reliever with full catching gear on. The kid looked at me like should I throw hard. I said he catches his brothers and both of them throw harder than you. When the coach finally realized who was catching in the bullpen, he yelled for #3 to get out of the bullpen and at his 2 backup catchers sitting in the dugout. We laughed about it after the game.
I think he learned from them and became more athletic through knowledge as much as physicality.