2012 is obviously a hoax, but try this on for size…

A little forewarning: The thoughts below are kind of jumbled up so deal with it. I’ll fix it up later when I think about more and organize my thoughts better.

So I feel the need to address something because while my friend was over we managed to get on the topic of ancient civilizations. After a few minutes I started thinking about the Mayans and their ridiculous calendar that is set to end this year on December 21.
So. The Mayan civilization can be dated back to c. 2000 BC and lasted up until the arrival of the Spanish conquistadors in the early 16th century which is roughly about 3500 years. They devised a way to keep time with their calendars and the Maya calendar is based around key principles that were used in the region and can be dated back to 5th century BCE. So this means that the calendar everyone is freaking out about began around 500 BC and was used until they mysteriously disappeared in the 16th century and therefore it’s only 2000 years old.
So this calendar expires on the year 2012 AD, December 21st. However, it is to my understanding that BC and AD is something that was only developed after the birth and death of Christ.
How did the Mayans know to count down to 0 to when this person they would have no way of knowing about was born, then begin counting up again after his death from 0 to 1 to 2 and so forth?
Secondly, what about the 33 period of when he was actually alive?
Thirdly, say they didn’t know about Christ. They still wouldn’t have known that they would have to start counting up. So what’s that about?
If modern people interpreted the calendar and figured it’s end was marked on 2012, that still doesn’t make any sense. With the account of Jesus being 31 when he died and we’ll just say that the calendar didn’t include that, then we should have seen the end of the world 31 years ago, yes?

I think, if anything, this just proves the 2012 doomsday prophecy to be a hoax because there are just too many things in the way time was counted between then and now for it to work. I’m just really confused on this whole thing and how anyone could possibly think it’s a possibility.