Bill, for me, atheism is one of those quaint vestiges of childhood, starting when I was 10 or 11, & ending at about age 19.
The realization that there was no God was quite a revelation for me as a child. It was impossible for me to conceive of something as always existing & therefore I concluded that there was no God. I realized that this was a minority view, so I didn't go around announcing my conclusion.

It did strike me as a bit odd that so many people could be mistaken about something that was so obvious to me, but it really was not a big deal to me. I just thought the whole idea of God & religion was rather silly. As far as I could see, it had no relevance to behavior.
I enjoyed science in school & later in college developed an interest in conservative political thought. I was an admirer of Wm. F. Buckley Jr., but for the life of me I couldn't figure out how someone of his intellect could believe in God. :S I tended to equate atheism with intelligence. Then around 19 I underwent a
consciousness expansion & the "simplicity" of my thought was altered & life was changed. I didn't believe in God, but the simplicity of my atheism was shattered. More later.