At dd's school it's year 5 - so age 9/10.
Dd doesn't want to and won't make her. She can't see a time when she will ever want to but does have autism.
Without that in mind this age does seem very young to me. Some of dd's classmates walk home alone and I have seen them screaming and shouting and messing about, running into the road without a thought as part of this messing about.
Just seems too young to me....