I started dressing differently probably well before age 3. I was already extraordinarily cunning at that age (I even knew how to purposely egg on certain games with my boy friends so that I could touch them, and I could remember entire zoology books in my head just by either reading what I could of them, or having them read to me), and instead of throwing a fit about dressing like a girl, I simply would not wear clothes of any sort cept undies and a huge sheet that I would tie around me like a dress. My parents didn't think a thing because they thought I was dressing like a superhero. As soon as I would get home from school, the awfully dorky boy clothes came off and I would wear the pretty, baby-blue sheet-cloth. I even invented a new type of dress with the cloth that I've never actually seen in a store anywhere to this day. And this was when I was 3-6! I wore that sheet almost every day of my life for years and years, I hated when I didn't have it.
And to this day, I do have the complex where I'll still wear the same article of any particular clothing for weeks on end if I get the idea in my head that it makes me somehow look more equal, soft, or female. Then, around late elementary, my sister was given a costume with a Gypsy dress and I had an absolute ball with it. It was so flowy, and it made me feel so empowered. My family thought it was pretty funny (surprisingly enough, in contradiction to how extremely hateful they were) because we all would dress up in silly ways at the time, but I secretrly adored the dress.
And to this day, I refuse to wear most male articles of clothing even though I do present myself as male at the moment. I have a very strict list of clothing objects that I'll wear, things that at least make me look slender and professional instead of the typical "auto shop worker" look you see around. I like well-shaped cargo shorts because they have the same shape as a skirt (triangled look), I love my blazer jacket because it looks very Ellen, and I usually only wear Sofia Coppola-type sweaters that make me look really soft. I really get very depressed and downright suicidal if I have to wear anything else.
On a side note, my first favorite cartoon villian was Andrea Beaumont on Batman, a woman who played Batman's innocent love interest by day and by night, dressed in a masculine phantom suit so that Batman would think she was a man and would never suspect her. Best villian ever!