So what do you propose?
Since we have no idea when an 11 or 13 or 15 year old going through adolescense - an age when most have some identity angst / crisis, and are easily influenced, and spend a ton of time online, and want acceptance, and think they know a lot more than they do, and all the other developmental aspects of that age - decide they want body parts cut off or hormones to permanently alter their growth and development - and we know that down the road some will regret it and feel mutilated and harmed and others will not - what do we do?
Do we cut off the breasts of all 11/13/15 year olds who feel confused through puberty and just cross our fingers that they are happy with it ten years later and say too bad so sad to the ones who are devastated by the mutilation of their bodies? Or do we instead say no, we are not cutting off functional body parts or permanantly altering your growth and development as you are a child and once they are adults they can make those decisions if they still feel the same way.
I was given the option of a major surgery on my foot at the age of 15. My primary (and developmentally normal) concern at the time was the kind of shoes I could wear. I really didn't understand the repercussions of the surgery from an orthopedic standpoint or what osteoarthritis would feel like down the road or what other potential challenges there would be. I was mostly interested in what shoes I could or couldn't wear and how long would I be in a cast and would it interfere with getting my driver's licence and would recovery interfere with some holiday plans I had. If I had the discussion about my surgery at 25 or 35, it would have been extremely different to what it was at 15 as my wordview, life experience, priorities, indpependence etc were all different.
Our minds and decision making capabilities are limited at 13 by not only brain development but by our narrow environment and life experience and by how impressionable and suggestible children are. So many detransitioners have talked about how they were just really confused and struggling at that age and as adults they realized that it was more about sexual orientation or about mental health / illness or about childhood trauma or about self hatred / not fitting in or about peer pressure / acceptance from the trans community or about vulnerability to ideologies when they were young or not understanding the ramifications for them. Is it fair to gamble with their lives and bodies?