It is the author of the book of Genesis who wrote that verse. I never claimed otherwise. He uses the same third person omniscient point of view for that verse as for the rest of the book of Genesis.

I never claimed it is a quote from God. What I claim is that it is not a quote from Adam. Whether it is said by God will depend on which view of scripture you hold to. If you believe in the infallibility of scripture, and subscribe to the view that God used the authors of scripture as a person would use a pencil, then that verse is said by God. If you do not subscribe to that view, then it isn't God saying it directly, but scripture says it.