Currently, it is the year 2018 AD (Christian calendar). And the year 1439 AH (Muslim calendar). And it's the 2nd of Nisan, 5778 (Jewish calendar).

So I'm afraid your basic assumption is wrong.

As an additional point, most modern, educated Catholics (and other Christians) know that Christ wasn't born in 1AD (there is no 0AD, it just goes 2 BC, 1 BC, 1 AD, 2 AD, etc), because the monk who worked it out made some mistakes. Herod the Great (who's mentioned as dying while Jesus and his family were in Egypt) died in 4BC, so Jesus was likely born in 6 or 7 BC. After all, believing Jesus was born in 1AD isn't actually official Church doctrine.