The Earth is 4.54 billion years old and the universe is 13.77 billion years, which is relatively new knowledge to us. That’s a long, long time, especially considering human history only goes back 12,000 years (Göbekli Tepe). Some cave drawings go back 40,000 years. There was a long time in between to get a lot of work done at God's own pace, which is probably slower than ours given that God is eternal.
I’m told the Hebrew word for “day” is “yom,” also meaning 24 hours, but it can mean more of a general time or period and can always be used metaphorically.
I’ve arrived at the personal opinion that the 6-Day Creation is a metaphor. I think God spoke "Let there be light," and the Big Bang happened. Over billions of years he tended to the entire project, watching it all unfold according to his will and his vision.
God could have very possibly used the divine and magnificent tool of evolution to create us, and it may have taken much longer than 6 of our days.
The fact that this may be the case doesn't harm my faith one single bit. In truth, it strengthens my faith. Now I don't have to ignore science. Everything is older than I had thought for many years. The Universe, the Earth, and ancient allegories, which reveal truth over millenniums, are all much older than I believed as a young man.
No Christian should have to fear looking at creation this way. It’s doesn’t make a single difference in how you view your faith. It was thought for millennia that the sun revolved around the earth. The Church believed it as well. Then new science and new information came alone. Now views are different.
The 6-Day Creation is probably an allegory, and it doesn’t need to trouble your faith one bit. In case you didn't already know, this view is nothing new. It's called Theistic Evolution.
On a side note, it could still be very possible that when his final creations learned how to interact with him on a personal level, they became Adam and Eve.