The Fall of the House of Usher:
“In the Beginning, God created the Heavens and the earth.” Gen 1:1
Then lots of things we don’t need to know about happened for unknown millions/billions of years.
Then Satan rebelled, and God wiped her clean: “And the earth was (became) without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.” Gen 1:2
Then the Six Days of Creation (of this world-age/Heaven-Age) began, cf Second Peter 3:4-6
I'd also submit that a "day" of creation isn't necessarily a 24 hour period, although back in the day we all thought it was.
I further note that the description of every "day" ends with "And the evening and the morning were the [nth] day"
Every day except one of them.