Common Era is functionally equivalent to AD, and refers to dates from Jesus' birth onwards. Of course Jesus' birth is now considered more likely to have occurred in 4-6 BCE, because of the constraint of being born before Herod the Great's death.

There is no year 0, because we are counting actual years, so it's more like 1st year, 2nd year, 2017th year.

The year Zero never existed, it was calculated to go BC/BCE321|123AD/CE. 1AD/CE was the Assumed birth year of Jesus. This Christian Accounting system was created in 525 AD/CE by Dionysius Exiguus, a Monk in the East Roman Empire. But it wouldn't see wide use until after 800AD/CE

I'm sure you are wondering what BC/BCE and AD/CE means. BC stands for "Before Christ" and AD stands for "Anno Domini" which is Latin for " Year of Our Lord" referring to Jesus Christ.

BCE-CE are very new terms meaning "Before Common Era" and "Common Era". These are meaningless terms used to secularize the Dating system