You're gunna have a lot of gods if we're having them exist as things start to exist XD. Just imagine God of Bread, God of Alcohol, Goddess of art, etc. Then we would get into some very whack gods as time progressed. I'd like to think the Gods came into being by being born by something, what that is can be up for debate.

In my opinion I don't think we should leave it up to worship for strength. Gods should just naturally grow more powerful as the ages go by, and if they ever take on new domains or steal another gods domain.