My parents are Christian, so I was raised to be Christian, but we didn't go to church very often. I don't ever remember a time when I "actively" believed in God; by that, I mean when I got to the point where I was old enough to question myself if I believed, there was never a time when I did. The earliest time I remember proclaiming my disbelief was around 12-years-old. I told my best friend that I didn't believe in God, then later that day, when we were in the car with my mom, my friend asks my mom, "Did you know HarlequinForest is an atheist? He doesn't believe in God." I was kind of embarrassed/scared because I hadn't said anything about it to my mom before, but she didn't make a big deal about it because, I think, to this day she doesn't believe I'm "really" an atheist, and that I'll "see the light" one day. At that time, I didn't even know what "atheist" meant.
Back then, my friend was telling my that I was gonna go to Hell, but when we were about 20, after not seeing eachother for a couple years, he told me he doesn't believe anymore either.