I don’t think it is really fair to say that the creation would be as eternal to God…there are different levels of eternity…
The creation is constantly changing, God is not changing… and while there was always some form of creation I don’t say that the physical worls always was… science clearly shows it has a beginning.
Also dont think it is fair to say that the creation would have the same nature as its creator… God is the ground of his own being, he simply just is (I AM). He is absolute being. Our existence and the creation’s existence is grounded in his existence. To say that the creation has the same nature would say that the creation can be the creation can be the ground of its own being. This would imply a second supreme being…
We can say that the creator exististed prior to his creation in a logical sense but the concepts of temporalness really only belong to our physical world and our own perception. We cannot apply that to God.