Scholars have different dates for the books of the Bible. Some scholars are conservative in their dating of the books, showing that the books were written earlier in history while liberal scholars place many of the books on later dates.
The most conservative date for the first five books of the Bible (Genesis-Deuteronomy) is placed around 1,400 BC, granting Moses as their author (Deuteronomy 31:9, 24). With these earliest dates in mind, the earliest the Bible began to be written was 3,421 years ago.
With the completion of the book of Revelation by the apostle John conservatively dated 95/96 AD, the Bible was finished. This is 1,926 years ago. If you go by liberal estimates, the Bible is younger than these early dates.
My problem with the liberal dating is it doesn’t accept the authors the Bible claims to be the author of the books. For instance, liberal scholars don’t believe Moses was the author of the first five books of the Bible. They believe they were written by editors who arranged the books from pieces of other books later on. But the Bible claims Moses as the author of these first five books.
They also believe that the apostle John did not write Revelation. It was written, according to them, by the community of the disciples of John the apostle much later on, into the second and third centuries. But Revelation claims to be written by the apostle John (Revelation 1:9).
Because I accept the Bible books’ witness of who their authors are, I go with the earlier conservative dates. They take into account the times these authors lived. Therefore, in my studying I have found it to be accurate to say the Bible was written around 1,500 years between its beginning and end by about 40 authors. It is about 3,421 years old.