When I was that age the fastest athlete in our elementary school was a girl. By 7th grade she couldn’t keep up with the boys. The difference in athletic ability usually doesn’t show up till later.
When I was coaching soccer, little girls at that age were also sometimes more aggressive than little boys, especially if they had older brothers. Some of them stuck with soccer and are playing in high school, but most of them lost interest as they got older, and got into gymnastics or horses.