i don’t understand your question. how old is too young for people to transition? 99.9% happen over the age of 18, and the very few that are under are through parental consent and to aid in depression and body dysmorphia. now, again with parent permission, some can get puberty blockers to aid in the dysphoria but those are completely reversible
“no gender affirming surgeries performed on youth ages 12 and under” “blocking gender-affirming care among TGD youth is not about protecting children, but is rooted in bias and stigma against TGD identities” “For teens ages 15 to 17… the rate of undergoing gender-affirming surgery with a TGD-related diagnosis was 2.1 per 100,000” or .0000021%. source: https://hsph.harvard.edu/news/gender-affirming-surgeries-rarely-performed-on-transgender-youth/
puberty blockers, whenever because they’re 100% reversible but let’s say 9 bc that’s the earliest you’ll see puberty start to be at play. for transitioning maybe 15 with parent and doctor consent (as it is everywhere). but it’s also not my decision for healthcare and we should leave it up to them