Hey Cassie.
I´m in a similar boat as you.
I´m 28, and I´ve had dysphoria since I was a teen, but I just didn´t realize back then that it had a name.
My family also thinks I´m moving "too quickly" but that´s simply because they never felt what I did and I never talked about it. When I told them about it, I had already made a decision, so they didn´t witness the whole process. That´s why for them it´s "too fast".
In my country they require a minimum of 5-10 talks with a therapist (one talk a month so amounts to half a year to a year, and a waiting time of four months for the talks). I think that´s a good thing, but I´ve got to say after 28 years of being a gender I felt awkward with, it would be nice to get a letter sometime soon. Not going to happen though.
Maybe you can explain to your family that they missed out on everything you felt throughout your life, so they can see that for you it´s not too soon at all.