“Not right in the head” is such a common assumption. So much so that I spent decades thinking I was crazy. It wasn’t until my psych eval. that I learned I wasn’t crazy at all.
Part of gender is a social construct. In that regard I’ve always been female. My body is the only part that wasn’t. I’ve tried and tried to make my mind match my body, but that always felt odd and stressful. I’ve finally given up and accepted that a better solution is to alter my body to match my mind. And thanks to modern medicine, I can do that. (Yes, I know this is called dysphoria and it isn’t unique to me.)
The net? I enjoy being female. It’s who I am. That’s why.