My son started training marksmanship when he was about 18mos, using small toys guns and plastic dinosaurs for targets. He shot a BB gun then a bit before he turned 2, and started shooting 22LR when he was 2. By 6, he was shooting centerfire rifles out to a half mile, and his 22LR out to 300yrds, and started wing shooting when he was 7. We started stalking rabbits when he was 4, but largely for show, as he wasn’t nearly stealthy enough at the time to get close enough, but by the time he was 6, he was hunting rabbits, squirrels, and wood rats. He went deer hunting at 7 for the first time. At 9 now, he’s getting big enough to shoot in competitive precision rifle and Precision Rimfire matches - PRS & NRL-22 matches.
Each child, and the parents which raise them, are a unique equation, so not all solutions will be the same.