I have a transgender child.
My child 'came out' before it was what it is now.
It's a long and difficult path, but starting hormones mean that the effects last forever, even if your child detransitions.
Even puberty blockers which are touted as 'thinking time' can have devastating effects and pretty much guarantee your child will go down the hormonal route.
As this seems pretty new and a shock I wouldn't be in a rush to start anything, don't give it too much attention, and quietly watch for a while.
Next step, for us, was getting a counsellor. I paid privately and got a counsellor who is gay. You can google counsellors who specialise in this area.
I also made sure I went through absolutely everything with my child. Every side effect, we watched operations, looked at lots on youtube of people who detransitioned and the consequences they live with daily, every story, video, blogs and anything else we found, we read so my child fully understood.
Don't put too much emphasis on feminine and masculine traits and hobbies, the traits your child has are simply your childs personality.
My child is now an adult, and is glad we waited to start the physical transition, although it was very tough at the time. It gave them more thinking time, time to be sure, and understand everything fully.
There is no rush, if your child is genuinely transgender, and it isnt just a phase, they have their whole life to transition. It's very important you dont do anything irreversible yet. No kid should be stuck with life long consequences of hasty decisions they made as a teenager.