Sports and extra curricular activities

I would like to get the groups opinion on sports and activites. My son is 6 and he currently does Jiu Jitsu twice a week, swimming 1 day a week, and basketball 1 day a week. He tells me and my wife that he loves doing all three, but at what point do you start eliminating activities and focusing one? I feel like if he doesn’t practice and focus on one sport he won’t get good and just be average at all sports. At what point do kids decide what they want to do? My son is also talking about wanting to play soccer, but we’re not allowing him to at this time.