I think you completely missed the point I was trying to make. Age peers are an illusion and only appears like a thing because most people follow a standard distribution; but this does nothing for the people who are further away from the mean.

Yeah, I routinely took classes with students 3–8 years older than me before going to college. "Age peers" are an illusion. However:

1. I mostly only cared about school w.r.t learning. For most kids, school is primarily a place to socialize.

2. If it took you two years to achieve the same level as what took someone else ten years (going with the 2nd vs. 10th grade example from a few comments up), I don't think you're going to get an appropriate pacing by just moving into the same class as them...

Maybe you missed when I said "generally". However you seem to be aware of standard distribution (ie generally) and then go on to talk about the edges (again).

I'm not missing your point at all. I'm talking generally and you're just stating (the obvious) that curves (spectrum?) exist and that some (~30%?) are outside the middle of the bell. Neat.

Since we agree there is a range of personalities and intelligence, maybe we agree that wide exposure to others (such as classmates) is, generally, a good thing.