The early Christians would probably have accepted the Old Testament Book of Genesis story of creation as literally over seven days. However, scientists have discovered more about how the world developed over recent centuries.
Theologians today often describe the Genesis six days of creation narrative as poetical rather than literal or historical descriptions. The thinking goes that the word days were not meant to be taken as a literal space of 24 hours but as six sections of unquantifiable time. The time we are now living being the seventh day
Temples in the Ancient Near East
Ancient temples could help us to understand how the concept of God creating the world in seven days developed for the authors of the Book of Genesis.
They were complicated buildings to design and construct, so their development planning was broken down into unquantifiable stages because it was impossible to foresee all the potential twists and turns.
Many temples were built in the ancient far east for various deities; King Solomon built the first Jewish Temple in Jerusalem in 1000 BC; enemies destroyed it in 586 BC. A second Jewish temple was built in Jerusalem sometime between 516 and 350 BCE; this was destroyed in the Roman-Jewish war of 66 CE.
Many other temples (to a range of other deities) were also built in these times.
It was believed that the Gods could only dwell within the walls of these temples and that they bridged the gap between humans and the divine. So, the book of Genesis writers could have used this well-known temple-building pattern to describe how God created the world.
However the world was formed, I have always believed that God planted a seed of his spirit within humankind at a certain point, whether at an evolutionary stage or in a creational beginning.
What is fascinating is that prominent theologians today argue that God built a temple for himself, more beautiful than anything mankind could even dream of, when he created the world as his ultimate resting place. Read more here – Creation is God’s Temple.