I'm always glad when another woman shows up on these threads to counter some of the regressive sexism expressed by the blokes. Particularly the regressive sexism of fellas like VIT who hold themselves up as enlightened and progressive, yet who express views so male-centrist and male-supremacist that they would have been called "male chauvinists" in the the 60s and 70s.
But I hope you won't mind me adding to the excellent point you made "about how it actually feels to be a girl" by making a small clarification for the benefit of all the LRC readers and posters who don't have a clue about what it's like to grow up female.
The experiences you mentioned as hallmarks of "the actual physical existence of being a high school girl" such as "dealing with periods, developing breasts and hips" are actually things that most girls have to cope with in middle school as well as high school. Some girls even have to deal with breast development and periods in lower school.
After all, the normal age for female puberty to start is 8-13, although some pediatricians nowadays say it's common and normal for girls to start at 7.
At any rate, most girls begin breast development when they are 10 or younger, and get their periods when they are 12. But some girls start even earlier. I have friends who had obvious breasts at 8 and started their periods at 9. I started my period the week I turned 11.
It's because so many girls develop much earlier than most blokes realize that the law in the UK says that schools must provide female and male students with sex-separate toilets and changing facilities starting at age 8.
Sexual harassment of girls by boys in MS, HS and even LS is already so rife that it's a regular weekly or even daily occurrence for many pre-teen and teenage girls. From my experience as a former girl and as a mother, I think sexual harassment of girls by boys in schools really ramps up starting in 4th, 5th and 6th grades.
Policies that force school girls in MS and HS to have to put up with boys who claim to "identify as" girls joining girls' sports teams, using girls' toilets and locker rooms, bunking with girls on overnight trips, demanding to be included in programs meant for girls such as health classes about menstruation, ovulation and the female hormone cycle - and getting the chance to trounce female athletes in sports competitions that are supposed to be for girls - have created new male forms of "male privilege" for boys who claim to be "trans" and "gender diverse." These policies give supposedly "gender special" boys a free pass to engage in new forms of male bullying and sexual harrassment of actual girls.
But the kicker is, the boys who are demanding and being granted these new forms of "male privilege" that no one else of their sex gets, nor are other males asking for, don't realize how entitled, pushy, selfish, sexist and "typically male" their behavior makes them seem in the eyes of many others. Nor do they realize that many of girls they're horning in on resent and dislike them - and are really put off by their entitlement, intrusiveness, arrogance and blatant, shallow sexism. These supposedly special boys also don't realize that some girls are creeped out by them.
But instead of being helped to see and accept the truth, the boys who claim to have special gender identities nowadays are being told by their parents, coaches, teachers and trans campaigners that they are most marginalized, oppressed, put-upon, victimized people ever to walk the earth. As a result, most of these boys really seem to believe in their heart of hearts that they should always get their way, no matter how negatively it impacts others.