From PZ's Place: Anna Yeung, on Why I Am An Atheist:

I was 12. Attempting to rebel, I declared that I didn’t believe in God. My parents didn’t really care, given that we were only Buddhist at funerals. I went through a New Age-y phase where I believed in astrology, the paranormal and spirits. But as I got older, I got wiser. I was a voracious reader, and came upon the multitude of crimes against humanity committed in the name of religion – its effects on women, sexuality and science. However, my turning point came in a grade 12 biology class. A girl who I couldn’t stand, who became brainwashed when her parents accidentally sent her to Christian camp, got up to do a project on evolution. She prefaced her presentation by saying she didn’t believe in evolution because of her religion, and then proceeded to talk about Australopithecus afarensis. That kind of dichotomy astounded me. Partially because I hated her, and partially because it was the only conclusion based on reason and logic, I became non-religious. But it wasn’t until I stumbled onto Pharyngula, that I realized that there was a name for it. Atheist.
Anna Yeung
Australia

Yeung makes two points:

(1)The religious commit crimes against humanity;
(2) A religious girl didn’t believe in evolution but discussed Australopithecus afarensis.

Summary: from a background of part time Buddhism at 12, and short term New Age, she became non-religious at grade 12, “Partially because I hated her, and partially because it was the only conclusion based on reason and logic”, and possibly due to the concept of evil-religion.