Creationists have adopted a biblical calculation that our universe was created approximately 6,000 years ago. But the genealogies of Old Testament are unreliable for several reasons. The idea that genealogies are there to prove the authenticity of creation, to nail down a date, and to preserve the lineage of the first humans, is a little unreasonable. Why would such a log be needed? First, creation would be a fact, and not need to be disputed; and secondly, the first families would be so small, there would be no need to record it, especially not in such a codified and specific manner. A major purpose of genealogies in ancient times was to separate groups of people into family and non-family. To me it seems illogical that Adam and his immediate descendants would require, imagine, or desire such an activity.
No, this kind of obsession with history would not be an immediate compulsion until people started to forget things. Eventually someone would notice that they couldn’t remember who his grandfather’s grandfather was, and wonder if they would be remembered. So oral traditions might solidify a genealogy for the purpose of preserving the lineage (this also assumes a detailed language was present).
Remember that genealogies were commonly used for political and social status in the ancient world. Claims of royalty and divinity had to be proven legitimate by genealogical documentation. Many times ambitious leaders had to fabricate family lines to justify their right to rule. Therefore, it is not such a big leap to me, that this kind of logic may be responsible for the genealogy recorded in the Old Testament.
Traditionally, the author of the Pentateuch is hailed to be Moses. We must remember that the story of Eden was passed down orally before even the time of Abraham, and Abraham was an origin story for the people of Moses. There should be a lot of speculation about ethos and accuracy of sources for the writer(s) of the Pentateuch.