Please note, no one is letting 13 year olds have life altering permanent surgery. At least not for gender transitioning. What is appropriate for a 13 year old is puberty blocking pills. These put a pause on the natural puberty. This gives kids and parents time to make important decisions. Without puberty blockers more surgery is needed in adulthood if the child decides to transition (breast removal for example) and some things like an Adam’s apple and deep voice are irreversible.