Hi! I didn't transition until I was 43, so congrats on figuring it out so young.
I did that COGIATI thing, as well as every other pseudoscientific (and I'm being generous about that) test on the internet. Every damned one of them told me I'm pretty much female. It wasn't anything I didn't actually know already, but I suppose I wanted some further evidence to confirm my suspicion. I had my wife do all the same tests just for giggles, and she always came out more masculine that I did.
I think the best and most accurate gender test is this question- Do you feel male, female, in between, neither or sometimes one or the other?
Please see a gender therapist before the dysphoria wrecks your life. I ended up trying to drink myself to death before I finally got therapy.