Carbon dating accurate not dht nodes updating
Thus, all living things on earth at any given moment contain about the same amount of carbon-14.
It doesn't work further back than 50,000 years or so, since anything older than that has very little carbon-14 left in it, but new techniques are extending that date range further back.
However, the carbon-14 already in your body starts to decay. Since we know more or less how much carbon-14 you started with, counting how much you have will tell us how long ago you died.