But, why do you say same-aged children? In the generally smaller communities of the past having [lots of] children of the same year of age would be much rarer.

In the village I grew up in the out-of-school friend groups were often across several years of age; and that's from a background of schooling.

Kids I know now, that are non-schooled, have very broad age-groups of friends and seem, to me, to be much more comfortable with company of any age.