I was completely oblivious to any sort of dysphoria as a kid.
I finally did start feeling it right around puberty... and the way that I realized that something was wrong was when I noticed that every single one of my guy friends was looking forward to the changes of puberty, but I was dreading them. They wanted the deeper voice, they wanted the body hair and facial hair and bulkier muscles. I didn't. I was terrified of my voice changing, I was completely disgusted by the prospect of growing body hair, and I felt like a hideous lumbering hulk of an animal due to the male muscles. Plus when I started seeing my pudgy young face become more adult, and people called me "handsome" and a "little man," I HATED it. Whereas what I saw the girls going through, for some reason it was what felt right to me. I wanted to have that smooth skin back. I wanted to be hairless again. I wanted more than anything to have my unchanged voice back. I wanted to be able to wear revealing clothes and show off my body instead of constantly hiding it because it was ugly. And most of all, I realized that erections and the entirety of my male anatomy felt wrong to me, while every single time I saw a girl, and realized what she had, I just felt so lonely because I felt trapped in a body that was fighting against me.
I harbored these desires, knowing full well that they were transgender feelings, for 13 years before finally doing something about them. And it took me to the point where I realized how miserable I was... how I had trouble talking to people, how I didn't seem to be capable of a normal sex life, how every single facet of my life was being hindered by my gender issues. And finally I decided that it was at least worth a try to change my physical body to the form that I had always wished it could be. And once I went on hormones, that was it, I was done, I knew that I had made the right decision. And now here I am a year later, becoming happy with my body again for the first time since I was 13 years old.