I've never felt comfortable with either of the "worlds" assigned to your birth sex and I've never felt that I would be transgender or any other end of the spectra either. I just don't want to define myself as anything that goes with whatever dangle between my legs or grow out of my body. And I don't want people to have prejudices just because "Look you have this and that now behave like it" or something.
Not too little, maybe.. 8-9th grade if we go really back (when people really thought it was a fun thing that i started growing armpit hair and didn't want to wear a bra.. and I've always been a tomboy or how i should explain it) but mostly in recent years when I've read about all the different terms and definitions that one definitely suited me the best.