End of the world theory, 12/21/12?

okay, well like some people i have been worrying about the 2012 theory of the end of the world, and one of my friends on Facebook stated on March 6th: "There have been about 514 leap years since Caesar first created it in 45 BC, without the extra day every 4 years, today would be July 28, 2013. Also, the Mayan calendar did not account for the leap year...so technically the world should have ended 7 months ago. Sit down Mayans." was his status, so would this be right and the theory way off, or what do you think?