Never known any other way, never needed to. Theism was never a factor in my upbringing and my parents encouraged me to find my own path. Teaching me to read before I started school probably helped; I've always been a voracious reader. No, the whole silly 'religion' stuff only impinged on my life probably in my teens, via the occasional god-squad friend, and I only really identified under the atheist banner once I got my grubby little mitts on the internet.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'