In the US there are plenty of places where children can get surgeries. This is a small sampling of the locations:
The Stanford Children's Hospital [1] will provide surgeries to both minors and adults. It doesn't specify how young the children can be.
The University of Illinois [2] will do surgery on people under 18, but doesn't specify how young the children can be.
The University of Rochester [3] will do some surgeries for people under 18. It doesn't specify the age, but it is under the "Adolescent Medicine" section.
Seattle Children's Hospital [4] will provide referrals for gender-affirming surgery to children as young as 9 so long as they have started puberty.
Looking at the links, none of them suggest that surgeries are performed on children. Puberty blockers aren't surgery. Intersex children are surgically mutilated without their consent but adult trans people need an OK from two psychiatrists. If I had had puberty blockers (reversible) as a child, I wouldn't have had to go through something painful. I was only able to start hormones at the age of 23 when all the changes had already happened. Hormones aren't able to reverse everything. Then people complain that we don't look good enough when we were never given the chance (unless you're rich enough to be able to afford surgeries, which I'm not).
The Stanford Children's Hospital [1] will provide surgeries to both minors and adults. It doesn't specify how young the children can be.
The University of Illinois [2] will do surgery on people under 18, but doesn't specify how young the children can be.
The University of Rochester [3] will do some surgeries for people under 18. It doesn't specify the age, but it is under the "Adolescent Medicine" section.
Seattle Children's Hospital [4] will provide referrals for gender-affirming surgery to children as young as 9 so long as they have started puberty.
[1] https://www.stanfordchildrens.org/en/services/gender/what-to...
[2] https://hospital.uillinois.edu/primary-and-specialty-care/su...
[3] https://www.urmc.rochester.edu/childrens-hospital/adolescent...
[4] https://www.seattlechildrens.org/clinics/gender-clinic/