Which is why Common Era and Before Common Era work so well. That they coincide with AD and BC is pure convention; the aim is to remove the religious bias so as not to exclude people of other faiths and none. Particularly as the latter reference an event of extremely dubious provenance which, even if it did occur, certainly didn't happen in the right year to make the system work anyway.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'