I'm a late onset, having gone through the whole I'm a cder thing. I lived with my GD, managing to have a life as a man, it was not until I was in my very late 40s that my GD kicked me in the teeth to remind that it was there. Therapy helped me understand that my past was a precursor and that I was TS. So no, in my case I "did not know" but it was there, I just managed to hide myself from it.