This is a purely HUMANISTIC opinion.
And the Bible began to be written about 4,000 years ago (with the book of Job), but that is totally irrelevant. It is the written Word of God, given by divine revelation.
As to abortion, it is murder pure and simple. The only difference is that the baby is defenseless.
You are wrong about the age of the Bible! From an interesting article:
The Christian Bible has two sections, the Old Testament and the New Testament. The Old Testament is the original Hebrew Bible, the sacred scriptures of the Jewish faith, written at different times between about 1200 and 165 BC. The New Testament books were written by Christians in the first century AD.
Source:
https://www.bbc.co.uk/religion/religions/christianity/texts/bible.shtml
The stories of the Bible first existed in oral form. From the 9th century B.C., a written language developed in Israel, and the oral texts began to be collected and written down.
People collected the words, stories, poems and sayings, but also official messages, for example from the surroundings of the royal courts. In places, the Old Testament itself gives clues as to which sources were used or where other material can be found. The best known is the reference to the "Chronicles of the Kings of Israel" or "Judah" (e.g. 1 Kings 11:41; 14,19; 14,29), in which one can read more about the deeds of the kings. Unfortunately, these documents are lost.
From the 5th century B.C., Jewish scholars then assembled the scriptures into larger units, starting with the Torah, the five books of Moses. The most recent books were not written until the 2nd century BC. Thus, from the beginnings of oral tradition to the last written records of the Old Testament, about a thousand years have passed.
The validity of individual books has long been controversial in Judaism. Presumably, the exact scope of the Hebrew scriptures was established towards the end of the 1st century A.D. In the centuries after the destruction of the temple and Jerusalem by the Romans in 70 A.D., Jewish scholars fixed the shape of the text down to the smallest detail. The Hebrew text thus edited is called "Masoretic text" because in its present form it is based on the "Masora" tradition of Jewish scholars ("Masoretes"). It is still the basis for the translation of the Old Testament.
An important note: Many of the stories in the OT come from the Babylonian captivity, were only rewritten in Jewish terms. So the story of creation and the tower of Babel. Everything is well documented. If there is interest, I take the time and search for evidence in the corresponding books.