Children need to be physically, mentally, and emotionally ready. First, children do not automatically develop the physical skills they need to kick a soccer ball, swing a bat, or shoot a basketball. They must learn these skills. Learning typically takes place with a parent or an older child in the backyard or in a park, or with a physical education teacher or a coach at school. Second, children must have the mental skills to understand the propose of the game and remember the rules.
Many children are mentally ready by about first and second grad.
Age 4 is typically too young. Third, children must be emotionally mature enough to display their physical capabilities in front of other children and parents. Ideally, they will enjoy playing with other children, be willing to compete and play fair, and not resort to tantrums or despondency after losing. Starting them too early can lead to frustration and burnout. Which sport A child's interest in a sport is the most important factor.