What do you have to believe about creation in order to be an elder at Bethlehem? How wide of a variance does this allow?
1) You have to believe that Adam and Eve were historical persons and that, therefore, there can't be millions of years between the first human being and now. That's because the Bible won't work for millions of years between Adam and Even and now. If you allow for gaps in the genealogies, then you might arrive at 15,000 years or whatever. So that's clear in our affirmation of faith.
2) The second thing you need to believe is that God created the world out of nothing. It is not co-eternal with God. We are not pantheists. We believe that God created the world.
3) Third, you need to believe that everything he made is absolutely good. He didn't create sin. He looked and six times said, "It is good."
We do not have in our affirmation of faith an old earth / young earth distinction: a seven day literal approach, or some kind of extended age theory, or one like John Sailhamer's, which says that creation is billions of years old, but God's action in chapters 1 and 2 of Genesis is a real, literal seven day preparation of the land for his human creatures that he makes at that time. So any of those three would be possible on the eldership at Bethlehem.