When did you become an atheist or agnostic?
When I was a kid they tried to make a Catholic out of me. However, they didn't start early enough, as I'd seldom gone to church before age 7 or 8. By age 10, I was having serious difficulty believing those God stories. This was the time of the Space Race, and I was intensely interested in science, especially astronomy. Science depicted a universe vastly different from that of the Catholic Church, which suggested to me that if we just stare at the clouds closely enough, we would see the unwashed feet of persons who lived in the Middle East two thousand years ago, and be looking up their robes, instead of seeing double stars, nebulae, etc.