The question assumes that God is a creature. God is categorically different from Creation, since His Essence (What He is) is Being Itself.
We can know this from the following argument.
1) Assume that every thing owes its existence, or being, to a previous being.
2) This chain cannot regress forever, since that would require the completion of an infinite series. A completed infinite series cannot exist in actuality; it would not be infinite or unending.
3) There must then exist a Being which does not owe Its existence to any other being.
4) We call this Being, God.
I usually cite mathematics as evidence for God, in that the universe (at least as we perceive it) requires sequencing of fields and particles that even here, billions of years later, has us looking back at that sequencing through the concept of number with remarkable understanding and derivative predictive power.
It is an error to assume that everything was created. The truth is...Everything which comes to be is created. God did not come to be. He is eternal.