Hi there!
I love the concept of the sun and moon.
And as I read what you have so far, it reminded me of a bit of mythology (I can't remember which, at the moment) when the sun and moon had a hard time meeting, but I'd be curious to see where this goes! Also, I do think using "god/goddess" is a little awkward. It might flow a little better if you used the word "deities" instead?
I hope this was helpful! 
-Cara