Because creation itself was done in a different dimension (before sin). But the creation had to work in both dimensions obeying the laws of both.
Man did not sin and change the laws of time by adding death until the end of the 6th day. Which means all of creation was done in a time-line known as eternity. But, creation in eternity means that anything can be created any age because it's age-less, or it would not be eternal.
So being able to do this, and knwoing how the laws would change when man sinned. How would a being create knwoing this so that the change of these laws would not destroy what was created?
Example: Let's say that the earth was created new. When man sins and the laws change. What would a new earth be? Molten ball. And what would happen to all created life on the planet? They would die. So God created the earth to be over 4 billions years old, so that when man sinned, all of creation would not be destroyed when the laws changed (death was added).
Here is a link that will help you better understand. It's a page I did that goes into great detail on the subject.
I fail to see what that has to do with my question.