There is yet still symbolism in the New Testiment, even as it testifies. I concede, I am not the biblical scholar that I believe you to be. But I do not recall Jesus' specific reference as fact to detailed accounts of what became the book of Genesis (He might have, I'd have to check context) As mentioned previously, Jesus taught in parables (symobolism) and certainly references the prophets and teachings. Jesus, The Father and Holy Spirit all maintain a similar style.
Also, I don't discount the knowledge our species has gained since those primative days in the garden of Eden ;O). How would we account for the existence of Dinasours ahead of Adam and Eve and long after the "6th day"? Our knowledge of the age of our planet is precisely the result of our eating from the tree of knowledge (along with our own awareness, right from wrong and evil). We learn, explore, create, invent, plan and we SEEK ANSWERS through Science all because God made us unique from the animals. Science has led us to conflict with the literal interpretation of creation documented in Genesis. I won't decide between what God has given man in word and knowledge. Instead, my faith has led me to seek and understand how to interpret the truth without conflict.
In short, I don't think God wants me to believe in a grand conspiracy about the age of the earth as proven by a hundred years of human science. Instead, my faith leads me to believe that before and during creation, God did not measure time in minutes, hours, days and years. But first people people new the sun came up and went down in a pretty routine cycle. I am not sure God is finished with Creation to this day. What might believers think of creation in 100,000 years when were are considered primative portions of our species? Science tells us we have only been intelligent for about 20K years depending on what you qualify as intelligent (unique among life on earth).
Jesus also referenced Moses in John 5:45-47.
Exodus is attributed to Moses who recorded in Exodus 20:11, "“For in six days the Lord made the heavens and the earth, the sea, and all that is in them, and rested the seventh day. Therefore the Lord blessed the Sabbath day and hallowed it.”
There are other examples in the NT that tell us the events of Genesis are not symbolic but literal events that did indeed occur.
I hope these examples aid in the discussion.
It really comes to do you believe God's Word?
If He cannot create the universe in six days, can He bring the dead back to life?