This is absolutely not a secondary issue. If you can prove that there was no Adam and Eve that all humanity comes from, then you can prove there is no such thing as original sin and the punishment for sin.
If you can prove the world is millions (rather than thousands) of years old then you can prove that death is not a result of Adam's sin. After all, death was around for a long time before "Adam" and "Eve." You are on the way to tearing down the entire Bible.
And, the type of literature is literal history - not very hard to understand. Jersus took The first several chapters of Genesis as literal history, Paul took it as literal history, Peter took it as literal history, James took it as literal history. Scientists for thousands of years took it as literal history.
I teach a class in Creation Science at Washington Bible College. Why not come down this fall and sit in on a class or two then see what you think about a literal interpretaion of this part of the Bible.
Or, perhaps, take a tour through the Creation Museum in Kentucky (right ouside Cincinnati, OH).