Painting the Boys Room

I am at a loss when it comes to interior designing! I have a plan though. Just not sure if it's a good plan!!! I need everyone's opinion! I was wanting to do a outer space theme. I will have pictures below for you to refer to. I will be putting in the fan below. I want to do the ceiling and the trimming in a dark color(the picture of the room is a Behr app pic, it's just an idea) then the walls a different color. The blue color is what I was thinking for the ceiling. The carpet will be a color matching the ceiling. I will also be putting wall decals on the ceiling, they're glow in the dark solar system decals. Is this a good idea? What should I change? Any ideas?!!!!