November 2013, just before the boom.
Previously, when I saw mention of Bitcoin in the media, it was by people who did not know what they were talking about. The one article that turned me off to Bitcoin in the beginning stated that Bitcoin was going to take down paypal. Now I don't really see them as competitors at all, but at that time I knew that eBay would determine who was king of online payments, and they own paypal.
In November I saw a couple of articles about people who had bought Bitcoins early on and forgotten about them then discovered they were millionaires. This prompted me to research what Bitcoin was all about.
Had I not read some misinforming articles early on, I may have been retired now.