I had never heard of Montessori schools before this thread so I'm sure there is more going on than I'm aware of - but I wanted to point out that what you describe here:
> school had about 15-25 kids / class year. Some of the larger years were split into two groups with separate teachers. Every year, maybe one or two kids left to go to other schools and one or two new kids joined, but for the most part I grew up with the same core set of children for several years.
seems perfectly normal from a UK primary school perspective (up to age 11 or 12 depending on the area). I'm surprised to hear that kids younger than that age would be expected to have larger peer groups in the US.
> school had about 15-25 kids / class year. Some of the larger years were split into two groups with separate teachers. Every year, maybe one or two kids left to go to other schools and one or two new kids joined, but for the most part I grew up with the same core set of children for several years.
seems perfectly normal from a UK primary school perspective (up to age 11 or 12 depending on the area). I'm surprised to hear that kids younger than that age would be expected to have larger peer groups in the US.