Asserting that "God is the one thing that did not need creating" is simply a blank statement without giving any reason WHY it ought to be accepted over the cosmos having always existed. There is simply no compelling reason for taking this statement to be true.
In fact, the idea that the universe has always existed is preferred, since it is simpler. Following Occam's razor (the simpler explanation is the better explanation), whatever argument requires fewer steps is more likely the correct one.
THEIST POSITION
1) The universe exists.
2) God created the universe.
3) God has always existed.
ATHEIST POSITION
1) The universe exists.
2) The universe has always existed.
The second of these has fewer steps, and therefore is the more preferable.