The Short Version
My gender identity is female. I much prefer to be addressed and thought of as female, though I understand this may be difficult for some people (especially those who have known me for longer) and will take time to get used to.
The (Slightly) Longer Version
Within the limitations of the socially-assumed gender binary, my identity is female. I have always felt that I was or "should have been" female, but suppressed this belief because I thought it was logically impossible and probably mentally unhealthy and/or perverted or something. (It was still the 1900s; we had some weird attitudes back then.)
Complicating this is the fact that my gender expression is much more neutral, consisting of a mix of both conventionally-feminine and conventionally-masculine traits – which is why I say my gender identity is more precisely described as "tomboy".