My family, school and everyone else in society made me cross dress. I'm actually a woman, and always have been. I just didn't look like one. So they made me wear this stuff and act certain ways. Once I transitioned, I was able to finally stop crossdressing and pretending to be a man, and wear clothing that makes a lot more sense to me - generally a dress and flats, and just be myself.
As to WHY that all happened? I think I'm intersexed - my brain is largely female, at least the bits of it that differ between genders, but the rest of me, as far as anyone has tested, was male.