In a recent Year 9 PHSE lesson at my school, we discovered that every single pupil believed men could change sex to the extent that they would be able to have babies.
(I keep telling this story, but...)
I remember reading about a "sex change" somewhere around that age, possibly younger, and being puzzled, because it didn't seem to make sense.
Nothing I'd ever seen about medical technology suggested that this would be the sort of thing we'd have the ability to do.
A short while later I managed to establish that they just meant a cosmetic procedure, and I was simultaneously relieved that I hadn't been wrong about lots, and annoyed that I was being lied to.
So I came out fine, but then I only had one single source that seemed to be isolatedly telling me about a "sex change", so skepticism wasn't too hard.
In an environment where it seems to be taken as obvious that girls can become boys, I can easily understand why any skepticism gets crushed because you can see lots of adults telling you that sex changes are possible.
You have to be quite advanced to spot that they're actually lying and using weird "definitions" of words (if you can even call them definitions) to make false statements true.
Sure, pigs can fly, and the moon is made of cheese, as long as you're free to redefine all the words.
And how you're supposed to have "informed consent" for puberty blockers at age 11-12. How many kids of that age must think they're really going to turn into boys or girls later?