European here, and my country is full of water (netherlands) I agree with you. At this age and if they have their diploma's (dont know if this is standard everywhere) you can pee. We dutchies put our kids at swimmingclass when they turn 4 so by 9 and 13 they   ought to know. At 13 we would go swim with our friendgroep unatended. Kids sound very shelterd. At 13 I was home alone to when mum bought dinner. But in the usa their is a lawsuit in everything so maybe thats why kids have a lack in independence maybe. Shrugs too