Since I was five or six I liked collecting foreign coins and paper currency. My mom often went on business trips, and my dad worked in Afghanistan on and off for several years so they'd bring plenty of that.
One time when my dad came back from Afghanistan he brought back a really ancient fibula which is what furthered my interest in antiquities.
When I was ten my grandfather died, he left us a sizeable collection of world coins, Roman coins, Ottoman coins and others. I was always fascinated with history, but it was about two years after that when I really started reading extensively about it. Naturally I started to take more interest in that collection and it gradually developed into a really fun hobby.
I guess that all of these factors combined pretty much set the stage for the inevitable.