Well as for stars, and light and everything, notice that God made light on the first day, and didn't make the stars and sun until the fourth day. That may not make sense to some, that there was light before there were light sources. But consider this. If he just made the light sources on Day 1, then people would say "hey it takes thousands of years for the light from all those stars to reach the earth" (in other words for the stars to even be seen). So it actually makes more sense that he put all the light rays in place (stretched from the planned sources to the earth), and then made the light sources.
Anyway, it's no problem for God!