I didn't 'know I was different' until I started school at which point I found out that I was different in a whole lot of ways, not just the gender deal. My first lessons in First Grade with good old Sister Rambo were of her teaching "This is an "A", it's the first letter of the alphabet and it makes a sound like "Aaaaaa' (she sounded like a sick cow, that phonics stuff sucked as a way to teach reading) so I asked if I could just read, since I knew that. I got a trip to the principals office, Sister Lucifer, where I had to prove to her that I could read, so she took me to the Monsignor, who also had me do stupid tricks, and in the end their sage advice was "I should learn with the rest of my class" at which point I did learn. I learned how to disrupt, attract attention to myself, cutup, and create first grade mayhem in the class room.
That I liked to dress like a girl at home seems like less of a problem than my constant behavior problems at school.