ummm, that's why God is uniquely called the "first cause." I sincerely doubt the professor hasn't pondered that--by definition God is unique and eternal...never having been caused in the first place...
Since physics nearly universally accepts the compelling evidence of the "big bang" theory were essentially everything came out of nothing (a singular point)-- ie. the Universe has a finite beginning...Who caused that?
Is the Universe "self creating?" What else do you know which has ever been self creating?
We know the universe exists (well, I do, you may be confused about that issue.) We don't know God exists. Asserting God as creator doesn't solve the question of how nothing created something (God.)
If God can always exist, then the same logic applies to the much simpler dumb matter that makes up the universe.