I was raised in a pretty religious home, went to church every week, sometimes twice a week. When I was 9, my grandmother died and that night I stayed up in bed for what I thought was forever (but it was probably only 930pm) trying to wrap my head around what happened to her, where she went, etc. I went downstairs and asked my mom and she told me "she went to heaven and she's watching over us right now." I asked her how she knew and she said she could just tell. Then I went back to bed and I realized I didn't think that happened at all, that she was just gone. That's when I realized I was an atheist.

For the next 10 years I stayed in the church, and actually became a pretty big part, playing in the band accompanying services and stuff, but I couldn't help feeling that I was living a lie since there were old people coming up to me every week telling me I gave them hope that the church wouldn't die since a young man like me was so involved and drawn to it. Eventually the pressure just became too much and I told my mom I was an atheist one day while we were making supper. She didn't believe me when I first told her and when she finally did she cried for hours. She told me I should talk to the minister about whether I should still be part of the church. I asked him to have a coffee with me (he's only about 40 years old, and I've known him since I was 7, so we're fairly close). We had a long conversation about theology and religion, and he told me he often doubts the idea that there's a heaven like we've been taught, but that he feels there's something more. He realized that I had no interest in being convinced that there was a god, but asked if I would still play music for the congregation. I agreed and to this day I'm still in the church every week playing with the band (I'm 22 now).

You might think that nothing changed, I'm still roped into going to church every week and pretending I believe something I don't. But it feels very liberating to have taken that weight off my chest with the people I thought deserved to know. And the congregation at my church is very close, and I think I would have felt an emptiness inside if I had just cut them out of my life, and I know It would have hurt them if they ever learned the reason why.

Tl;dr: when I was 9 when my grandma died. I thought she disappeared instead of going to heaven.