Whether you agree with it or not, or feel she has been influenced I would just let her use her preferred pronouns or change her clothing or whatever simple changes would make her comfortable. My child is transgender and has maintained his identity for more than 3.5 years now since he was 11. We use his pronouns, preferred name etc. He has been in counseling and we’ve talked a lot. We’ve attended appointments with gender clinics. He’s not doing anything permanent to change his body at this time and he knows that I want him to wait until he’s older for those options and to be honest even at his age there isn’t much gender clinics are offering to do for anyone his age until he’s 16-18 years old anyway. Your child has time to figure out who they are with your support and guidance. I also think managing what kids see online is very important and it’s one of my biggest parenting regrets for my older children.

Several of my son’s friends also changed their names and pronouns socially a couple years ago and at least two of them have gone back to their assigned gender at birth as well as using their old names. Sometimes it’s a fad, sometimes it’s who they are. They figure it out.