When I first found out about the sumerian tablets

For me it was the the inability to reconcile scientific facts with religious teachings, and believing that such things as the laws of physics (radioactive decay of rocks being used to determine the age of the earth) haven't changed.

I used to be in a group of friends back in middle school. One guy told cool stories like self aware rocks and that he knew top secret science and stuff and we believed it. Made me realize how easy it was to believe in something silly and how gullible I was. Not that I was heavily religious to begin with but it was an eye opener.

It came in two stages: 1) I rejected the organization of religion, i.e. the churches, the bible colleges, etc. thanks to the overt hypocrisy, and 2) I later lost my belief in God by deconstructing my faith only to realize it was based on falsehoods.

So, it was a process that was well thought-out.

I rejected organized religion because of all the hypocrisy, misogyny, racism etc. I saw in the various churches I attended--some of it from those who stood behind the pulpit every Sunday. I did not become an atheist until I started learning more of the science I had been taught to fear and ignore.

I saw the hypocricy at a very young age. I was never a theist.