I agree with this entirely.
It sounds like for the author, transitioning was a positive thing and I wish him all the best and hope he continues to be happy in his decision. Of course there will be others like him out there, but in relatively low numbers.
However there are many many teenagers out there who are vulnerable to gender ideology and could well end up going down a medical pathway and hugely regretting it later. The consequences of this are not minimal. They include being made infertile, loss of your breasts/penis, loss of sexual function, being a medical patient for life.
I think it's terrifying that teens (and young adults) are being set on such an extreme medical pathway when we don't know how many will regret it long term.
I am sure this book is telling the author's story in a genuine way, but I also think it unfortunately contributes to a dangerous narrative for young girls.