I used to think it was because He was an *expletive redacted*. But then I realized that it wasn't that I was born wrong, it's that the everyone else kept telling me I had to be and act like a guy. I know who I am, and my body has never defined me. God helps those who help themselves, and I needed to get to a place of peace with myself to be happy in the first place. If I had been born cis, I wouldn't have had to struggle internally to the same degree, but I doubt I would have the self-assurance and conviction in knowing myself that I do now.
Also, I don't really like the word transsexual, since it seems to me if you compare it to asexual, pansexual, bisexual, heterosexual, homosexual, it doesn't fit. It would fit if transsexual meant someone who is attracted to transfolk. But it is about gender identity not sexual orientation, simply because the cis people who came up with the term fundamentally misunderstand us. It's why transgender or trans, although less specific, is a better term imo.