To me it is very clear that "it was evening and it was morning, the third day" is clearly intended to indicate one revolution of the planet. Genesis goes out of this way to make the point.
God does use sevens and sevens of sevens to describe many different time periods, but in the creation story, and the Fourth Commandment, it couldn't be more clear.
Your problem comes in not acknowledging the power God has over his "simulation". He can create the components of a 13.8 billion year old universe in six days, and assemble them in any order He wants. Just like the author of a virtual reality game might create its avatars and layers in any order.
If we are living in God's "simulation" (which he not only created but actively sustains), then you can infer nothing from scientific observation about how it was created... or even whether anything that "exists" now has existed for very long at all.
RE: Were the seven days of creation in Genesis seven twenty four hour periods? - Delving a little deeper