That's the first time in my life I've seen a middle schooler in manga that actually looks like IRL middle schoolers in Japan. Back when I was there I was pretty surprised by how, well... Not "fat," but really, most of the pubescent girls I've seen seemed kinda chubby. Add to that being really short (I mean, we all know it, but seeing it myself was still effective, and I'm an average height guy) with actually the adult person's body width, and, well, I don't think it would be an exaggeration to call anime female teens a different species from Japanese.
Surprisingly, I think only teen girls are special in that way: kinder gardeners and high-schoolers seemed more similar to what we have in Europe, though the girls still looked a bit round. Maybe that was just the area I was mainly in, though (Okinawa). Didn't get to see that much people on the mainland, though the ones I've seen didn't look that different from southerners natural tan aside.
Compare to this random google find:
See the difference in proportions? Anime females have very different leg-to-body ratios than real life ones. And since the actual character's height is generally the same in relation to things around, it creates basically a population with same height, but very different body ratios. It's kinda uncanny when you actually think about it. Like, can all this really be explained just by appealing to western body types? But Japanese are Japanese, a normal Japanese person would find their kin more attractive, at least generally speaking. Same with every racial group.
Oh, and I never saw a school skirt shorter than around knee level or maybe minus palm. That's a fucking myth all right.
P.S. Oh, I got what's the most different. The nose. In this chapter's girl case it looks kinda like the real thing. Obviously don't want to sound racial, just pointing out that the biggest difference between Asian and Caucasian faces is actually the nose, not single/double eyelids. I got used to my Asian colleagues' eyes pretty darn quick, but even now I still can't help noting the unique nose form.