It's no secret, I love comic books. But the main problem with superhero comic books is the convoluted mythos. A hero's origin is constantly changing, sometimes with subtle details and other times a complete overhaul. DC Comics is currently rebooting all their titles (proving my point once more), so Catwoman's origin will undoubtedly change again. Meanwhile you can read all about Selina's troubled childhood and her transformation into a supervillain here.