The couple in the Genesis named Adam and Eve are not the first humans and the Bible does not even imply that they are. They are noteworthy because God chooses to overtly interact with them and have a record of those interactions recorded for posterity in the Bible. There also are other theological interpretations we need not get into here. But this happens many other times in the Bible. For example, God chooses, seemingly out of the blue, to interact with Abraham, and no explicit reason is provided to justify this choice.
Hope this helps. I am trying not to wander too far off topic here.