That's a poor argument and you risk your credibility when you make that argument.

The argument is called "god of the gaps". You are claiming that because we don't understand how something works, it must be the work of a god. That argument has been shown to be wrong a countless number of times -- lightning, earthquakes, floods, etc. Consider a magic trick where the magician produces a rabbit from a hat. You can't conclude that it can only be a supernatural act of magic just because you can't figure out how the magician does it.

It is also circular reasoning. You can't say that the universe can only exist through a god without first showing that a god actually exists. If the existence of a god is necessary for the existence of the universe, then you can't use the existence of the universe to prove that a god exists.