For the longest time I thought I was the originator of 'xbone' on the internet.
So tonight I did some personal research, and the first time I used 'xbone' was at 4:38 pm est on May 21st, 2013. The Xbox One reveal event was on May 21st 2013, starting at 1pm est and ending at 2:04 est.
Sources:
Forbes article with real time analysis of the reveal event
edit: and for fun, here's a kotaku article discussing the same thing as OP, 7 years earlier.
I know you couldn't have forseen this happening, but congrats on creating an awkward, boring gamer joke that looks set to live for at least a decade.