Didn't take long for me either. I was on a really small dose for three months, then it doubled to about a half of what I take now for three months. I started passing, although as a very young man or boy, during the second increase. I wasn't actually even ready for it, because I never did any RLE and hadn't started dressing male or binding or anything, just dressing androgynously and suddenly people were "sir" all over the place and I still had boobs sticking out. Was a bit awkward.
Dennis