Massive merailing. So, ignoring the merailing...
Thank you Helen for coming and sharing your views and experiences with us, I find your openness and honesty very refreshing.
Thinking back to when I was around 12 or thereabouts, trans wasn't really much of a thing, but at my school what was a thing was being bisexual. I'd say roughly every 3rd girl in my year claimed to be bi. Before anyone says it I'm not saying sexuality and gender are the same, just pointing out how something which is, IMO, quite core to someone's identity can still be very much subject to fashion.
Since we left school, several girls have since settled with female partners, and some are married to them. What is interesting is that the group who are with female partners, and the group who claimed to be bisexual, are entirely distinct from each other. Some of those bisexual girls could of course have settled with men, but I am not aware of a single one who is with a woman or who has even had a female partner. Most of them just quietly dropped the 'bi thing' around 15/16/17 and never mentioned it again.
Note. I'm not in any way dismissing bisexuality - I am aware there are bi posters on this thread and that's absolutely not what I am getting at. But identity, when you are a tween/teen, is one heck of a fluid thing and I'd say very very heavily influenced by friends, peers, trends, and hormones. I don't believe medicating for identity reasons, suppressing hormones and blocking puberty, is the correct choice.