BC/AD doesn't have that great a foothold, in any case - it seems "Anno Salutis" and other versions abounded before anyone got used to BC/AD. Jews and others do not object to using the same calendar that dominates Western society, they object to a naming scheme that states quite literally that Christ was the messiah.
You may be interested in some background on BCE/CE and an article including reasons some non-Christians prefer BCE/CE. It is an effort to be more inclusive, not a personal insult by way of putting you through the anguish of having to detect a ‘B’ or the lack thereof.
Prior to the 6th century AD, many Christians who didn’t use an Anno Mundi (in the year of the world) type system relied on Roman dating, either marking dates from the year legend had it that Romulus and Remus founded Rome (753 BC) or by relying on the date system established under the Roman emperor Diocletian (244-311), based on the accession of Diocletian.
The meaning of AD is Anno Domini or Year of our Lord referring to the year of Christ’s birth. Today, based on historical evidence relating to Herod and astronomical evidence relating to eclipses and star novas, most historians believe Christ was born a few years earlier. (That’s the reason purists insists the 21st century began January 1, 2001.
He decided to start his 532-year cycle from 753 years after the Founding of Rome.
So the first year of the 21st century begins in 2001 AD and ends with the beginning of 2002 AD).
It took about 400 years for the dating system devised by Dionysius to reach common usage.