I can only speak about my DC and this shouldn't be considered anything other than that.
I think it's relevant that my DC was diagnosed ASD age 3.
Age 13ish they we're in a really bad depression, CAMHS etc and started on antidepressants. When they started coming out of the worst of the depressive fog, they announced (at school) they were trans. School immediately affirmed, names pronouns and told us after the fact. DC had an EHCP and various professionals involved. The OT was pushing for Tavistock referrals, the school made noises about reporting us to SS as "safeguarding" as we weren't affirming. We did buy some skirts and leggings but said it was too fast and too soon to be changing names and pronouns.
DCs psychiatrist noted the identity stuff occurred at a point in their medication that was known to be a peak with suicide attempts. The psychiatrist explained how the medication can make some feel invincible and overwhelmed with feelings they haven't experienced before.
We didn't make a huge deal about anything just restated to DC it wasn't something to decide upon until they were at least 18. They didn't want the Tavistock referral as they hate talking about themselves. I'm aware that appears contrary when they've made statements about their gender identity, but I'll let MN feel victorious on that one 😅
Anyway DC went to a different setting for post-16. Kept in touch with their school friends (all autistic).
Around 17 DC told college and us they had been identifying as NB to their friends and told us the new name. We decided to affirm and we tick along nicely now.
DC is a gentle soul and really isn't an attention-seeking narcissist. They're very introverted and live very quietly.
We're at peace with it all so I'm unfazed by the vitriol on threads like these.