... Can prepubescent children get anywhere near how seemingly tall this girl is? Just wondering, is all.
Sure, in fringe cases: https://www.littlethings.com/robert-wadlow-tallest-man
Dude was 6’5″ when he was 10 years old. ϞϞ(๑⚈ ․̫ ⚈๑)∩
I had a classmate in elementary school who was taller than most of the parents (he transferred to our school in third grade, and by that time he'd already reached that insane height).
I ran into him again in high school and he was even taller. Like, we're talking Shaq levels of height, here.
First, I was talking about non-fringe cases. Not that extreme, anyway; Wadlow had a medical condition that made continue to grow even as an adult, which ultimately led to serious health problems towards his later years (he needed braces just to walk, and suffered from high hypoesthesia in his legs and feet) and eventually death at a mere 22 years of age.
Second... and there are people who say that adolescent/adult-looking preteen characters from anime/manga are mere fantasy.
Its an actual thing though.
Everyone goes through puberty. It’s a normal part of growing up. But when a child goes through puberty sooner than normal, it’s called early puberty, or central precocious puberty (CPP).
CPP is triggered when the brain tells the pituitary gland (a bean-shaped gland located at the bottom of the brain) to release “puberty” hormones called gonadotropin-releasing hormone (GnRH) too soon. The result is that girls start producing estrogen, boys start producing testosterone, and sexual development begins.3
More then likely thats what she has since it can start at the age of 5.
Without applying anime logic, this is probably what she has.