A woman who has posses a body of boy as half as her original age

Despite being a genius I was living my life just like any natural being but why do I have to die and enter into someone body who is just a jerk and top of that I was woman or should I say I used to be a woman but now I am in a man's body. "Are u serious" after opening my eye in private room of a bar I found myself naked and why I am so calm. Why is my memory so clear that it seems like I was living in both body as a girl and as a boy at the same time with totally different personality.