Christianity is not 2000 years old. It is far older. In fact, it is as old as the human race.
That might seem like a remarkable statement, but any confusion or incredulity you might have is due to a lack of comprehension about what the Christian religion is actually about. It’s about certain promises, and those promises date from the dawn of time.
Christianity is the same religion as Old Testament Judaism and the religion practiced by the Patriarchs from Adam to Abraham. Of course the name and some of the trappings have changed, but the promises and much of the daily experience have not.
The promises have been the same right from the beginning, that God would provide a Son—a Messiah—who would conquer sin and death.
We have always had to make symbolic outward expressions of our faith in God’s promises. In ancient times those symbols involved ritual animal sacrifice. Today it involves baptism and the communion ceremony.
The ordinary daily experience of meditating on the Word of God has remained the same. Today the Word is delivered to us through preaching and reading the scriptures, and in ancient times it was delivered through prophets, visions, angels, and direct revelation.
The practice of gathering together on a weekly basis to worship and reaffirm our faith in God’s promises has also always been with us.
Some confusion as to the true antiquity of Christianity may be due to the fact that Christianity and Judaism are today two very distinct religions. I can clear this up by pointing out that modern Judaism is not the same religion as Old Testament Judaism. Modern Judaism arose as a means of preserving national Jewish identity after the destruction of Jerusalem in 70 AD. Modern practitioners of the religion self-evidently do not believe the central promise of the Old Testament, a savior sent to deliver Mankind from sin, and whatever roots their religion may have in the Bible, they have been completely obliterated by 2000 years of rabbinical gobbledygook. The only similarity between Old Testament Judaism and modern Judaism is the ceremonial law. If they actually believed the Biblical symbolism behind these ceremonies, they would be Christians.