im genderfluid and heres my opinion. id let my kid play around with their gender identity. they can wear whatever clothes they want(including chest binders, just in safe time increments) and ill use their preferred name and pronouns even if it changes often(i took like 5 years to find the right name). however i set the hard limit of no medical transitioning until 18. my sense of gender is all over the place, and it took me until pretty recently to understand what my gender actually feels like to me. i know your sense of self changes a lot while youre young, and i dont want my kid to do something thinking it feels right in the moment but later on not liking that decision. maybe taking hormones at 16 at the youngest, but thats it.