The last time I coached soccer(Park District) my kids were maybe 7 to 9. I coached for 3 seasons and we never lost a game and never even had a close call. That wasn't because of my coaching acumen as opposed to my "team building" skills.
By the luck of the draw the 1st year, I had my twins who eventually played high school sports, albeit not soccer and 3 other kids who played soccer on scholarship in college with two of those eventually playing semi-pro in England. I learned a neat trick in that, even though the players were assigned randomly, our Park District allowed me to pick my two assistant coaches. It wasn't hard to figure out who to pick as assistants. Those 5 kids are still friends, although somewhat long distance, today more than 20 years later.