Idk about how it's in china, but back in my middle and highschool year, it exist. The girl was so beautiful, that the whole school called her similar to school flower. From senior, sophomore, to junior. many boys pursued her, including me haha. We didn't shout like 'oooh that's her' and gossiping too much like in the novel. But when she appears, the whole school immediately focused on her lololol.
the terms 校花and校草 exist, at least I've heard them by some radio dj and on (somewhat) boomer TV series I'm not sure if the term is also used in China, but very likely yes
We had a really pretty girl, but instead of gasping at her beauty the boys just teased her a lot. We were 10. (BTW, I was not one of those boys. I lost to her in arm wrestling once so I kinda avoided her to not get reminded of how I lost to a girl.)
In China, yes, it exists. It’s most definitely dramatised, but a lot of schools have some ongoing discussion on who is the “school flower” and “school grass”. It’s not to the point in novels where the whole school gossip revolves around them and their friends, but for example if you ask a student who the “school flower” in their school is, they’d be able to answer with a “isn’t it xxxx?”. Not all schools though.
No, in my experience it doesn't exist in germany. Besides, everyone has different tastes and beauty standards. If you are talking about a deeper attraction, then you have to know the person to some extent (or at least let others think they know you/ idols f.e.). Only external appearance doesn't cut it, to create a long term "school flower" type of person. Appearance is shallow and the affection fades in short term anyway.
I think pretty much everywhere general people are aware of the most attractive people in school? It's just rare for even one person to be exceptional enough that people obsess over them. I remember in my high school (America) I spent time with some people who could be called school flowers / school grass (who told that guy to be handsome, smart, and talented in both sports and music? And from a decent family? And hardworking too?) and other students would just flock around them. I don't remember anyone being called by a title, but maybe that's because I wasn't interested in that sort of thing and didn't even bother remembering most people's names. Still, there were a handful of boys and girls who stood out like that. If anything, the term "prom queen/king" is the closest thing we usually have, otherwise they're just the popular crowd. (I'm out of date though, maybe current school kids have a term) My school also had a bunch of clowns who stood out even more than the good-looking ones, so the conversations usually went the direction of what silly thing they did...