I do think that it should probably be something to wait on as it is such a big decision and while some children really do know who they are when they’re very young, many do not. As a parent, I would probably follow your ideas which would be to allow them and encourage them to express themselves as they wish. I’d also want them to have a developed mind to make the decision to transition for themselves, because it is such a long process as you’ve said. If it could easily be done and undone (and weren’t so expensive), I’d encourage my child to make the decision for themselves (maybe someday in the future that will be possible), but since it’s expensive, difficult to do, and probably difficult to undo, I imagine I would want them to wait. All of that said, I know that it’s really difficult for kids who know who they are to have to exist in a body they don’t feel comfortable. Perhaps, money allowing, I would encourage therapy to allow them to cope with that stress in the time being.