Short answer: because I am a woman. Plus two more questions...
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.
The hardest part of admitting I am transgender was admitting it to myself! Telling other people was easy. Plus two more questions!
I’m not sure exactly what the first time I wore women’s clothes in public really is for me — there are so many ways to look at it!
“She said she can’t play with me because I’m a boy, but I’m not. I’m a girl!” The adult laughed and told me “don’t be silly, you are a boy.”