Another question disputed for ages causing Christian unity to be split into thousands of sects over interpretations of the Bible.
Some examples - you may wish to add more.
The seven days of creation - allegorical or literal truth?
Science has proven the earth is 4.5 billion years old.
Adam and Eve - Allegorical or literal?
The Second Coming - Riding on a cloud with angels - literal or allegorical?
Christ said ‘let the dead bury the dead - literal or allegorical? (Luke 9:60)
I tend to believe that there is a combination of both. Jesus often spoke in parables, since this was an easier way to create understanding in common people.
Mathew 13:31-32
He put another parable before them, saying, “The kingdom of heaven is like a grain of mustard seed that a man took and sowed in his field. It is the smallest of all seeds, but when it has grown it is larger than all the garden plants and becomes a tree, so that the birds of the air come and make nests in its branches.”
The Kingdom of God is not tiny like a mustard seed. But this parable shows something that seems to start small, and not too impressive, becoming the larger than the rest in the garden of knowledge.
As far as the age of the universe, the science estimate of 13 billion years is based on earth time, which is used for practical convenience. This is a parable, since earth time is not the universal standard of time, due to the earth being the center of the universe. Aliens, if they exist, may not use earth time as the universal standard.
The Earth was not even around for the first 7-8 billion years of the universe, to be a valid universal standard for all time, since the BB. In terms of Genesis, it is not clear what time reference the writer of Genesis was using. But it was not earth time. He never said earth days, which would have been false, since this is not the universal standard, like the science parable; mustard time seed.
If we apply Einstein's theory of relativity; relative reference, to the 13 billion earth year parable, we would need to be in a reference very close to the speed of light, for those13 billion earth years to time dilate into one day. At the speed of light, time stops.
In Genesis, God says let there be called light! Light travels at the speed of light, which is needed to make the Genesis claim of one day to form the universe valid; God reference was very close to the speed of light.. How would the ancients stumble onto this modern reference time conversion, that is also consistent with God and the light claim; speed of light? Is it coincidence or inspired?
In terms of the science parable, of earth time being universal, and the earth reference for telescopes the center of the universe, each day of creation takes less and less earth years. Life only takes about a billion years. The sequence of diminishing time, would suggest God was slowing his reference from the speed of light; let there be light, to less and less than the speed of light, until God becomes man; Jesus. Then God and earth time references match. Although some miracles, which speed up healing, may have been time dilated; time potential added.
I would be more comfortable if science would use actual space-time references, for the formation of the universe, instead of dumb it down with universal earth time, even if this is a useful parable.