BTW: It would actually be Carbon-14 dating, not Carbon-12. 12 is regular Carbon: 12 protons, 12 neutrons. Carbon-14 is an isotope of Carbon-12, having 2 extra neutrons.
“Radiocarbon dating, or carbon dating, is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 (14C) to determine the age of carbonaceous materials up to about 58,000 to 62,000 years.[1]”
http://en.wikipedia.org/wiki/Radiocarbon_dating
Ugh!! Make that regular Carbon (Carbon 12) has SIX protons and SIX neutrons, while Carbon-14 has 6 protons and 8 neutrons.