I wasn't too bothered by my genitals most of my childhood, but I did notice it from time to time. Sometimes I got envious of boy's genitals and wished I could stand to pee, but most of the time I didn't think much of my own parts. I had no idea what so ever if I saw myself as male or female before puberty, it was a concept I just couldn't grasp. I just saw myself as a person, or sometimes as devoid of gender. I did have envy for boys' bodies while feeling kinda "meh" about girls', but that was literally the only sign of me being trans as a kid.
I did try to stand to pee once or twice but only could if I was outdoors and not wearing anything at all on my lower body. I didn't really make more of an effort than that, but just complained about the inconvenience instead, then forgot about it later. I had no problem running around naked or letting others see me, although I was told several times that I was being inappropriate and needed to put on clothes. I just didn't understand what the fuss was about, cause to me genitals weren't more special or whatever than elbows or feet or any other body part. (Learning social cues while asperger takes a bit longer.)
I don't know, it's hard to say what/when were my first memories about it, it probably got into my mind after having seen something on TV or in a movie, or seen some random boys run around naked at a beach or something. I didn't have friends, male or female, at that age so I didn't really know anyone I could compare myself to, except from my sister.
At age 9 I got a lot more aware of my parts though, cause after my bullies sexually abused me and that lead me to start "exploring" myself I got ashamed of my parts, however that had little to nothing to do with gender dysphoria. Although it was certainly some other form of dysphoria. Keeping my gender issues separated from my trauma issues has been difficult at times, but ultimately and at this point, I do know which is what.
I didn't really start getting lower gender dysphoria until a lot later on in my teens, when I started to actually think of myself as a guy. Before then it was just confusing, also in retrospect.