Every person’s experience is different; there isn’t a universal answer to this question. Further, there are different ways to interpret the question which can lead to vastly different answers:
If you are meaning “when did you first know you were not the gender assigned to you?”, for me the answer is that I told people I was a girl when I was 2–3 years old. I had been playing with another girl in a nursery and she suddenly stopped and told me “we can’t play together because I’m a girl and you’re a boy”; my response was to protest “but I’m a girl!” When a parent came over to see what the fuss was about, I told them “she says I’m a boy, but I’m a girl!” I was very confused when the adult told me that I was a boy – I wondered “how do you know? You never asked me!” I have many memories of similar times when I spoke my truth and was told I was wrong. I learned that this was something I should never let other people know because not only would they tell me I’m wrong, they would laugh at me and make fun of me. I entered the closet before Kindergarten!
If you’re meaning “when did you first use the label ‘transgender’ to describe yourself?”, then my answer is around 40 years later. While I’d heard the terms transsexual and transgender from my teen years onwards, I was too scared to ever apply those words to myself. By that time I had learned the lessons of my early childhood that to let anyone know that there was anything feminine about me was about the worst possible thing, and this has been reinforced by the representations of trans people in the media: Jerry Springer, Maury Povich, Geraldo Rivera and their ilk regularly used trans people as villains and punchlines in their shows, and movies like Ace Ventura and The Crying Game taught me that trans people were abominations — there was no way I could be like that!!! It’s only more recently that the combination of improved media representation and the building internal pressure and turmoil from suppressing and hiding this fundamental part of myself combined to force me to face what I’d been feeling my entire life and finally accept the truth about myself.
Since people seem to use the terms interchangeably, I’m asking for clarification. Do transgender people feel like they were born the wrong sex or the wrong gender?
I can only speak for myself.
I feel that I was born with my sex and gender misaligned. For the first 40+ years of my life, I worked hard to try to get my gender to align with my body’s sex, but no matter how hard I tried, it never really worked.
Once I accepted that I am trans, I let go of trying to make my gender align with my body, and instead worked to get my body to align with my gender. This has been infinitely more successful and satisfying.
Basically, we can change our bodies, but we can’t rewire our brains. And so the treatment for transgender people is to help them bring their bodies into alignment.
So to the extent that there was something wrong, it was that my gender and sex weren’t aligned. My body was healthy and whole, just not the right configuration for my brain, and vice versa.