So when I finished Story Mode defeating the hardest boss in the game (Newton as a Titan) I thought to myself "Since we got all these materials why not decorate, our moon, and earth ."
So I hoped on my Pod Computer (The controller), and went to the following.

Me -> My Earth -> Profile
"Huh that's strange I can't decorate my earth, maybe its decorate."
(Exists out of profile, and the earth)
Me -> Decorate
"Okay we can change, our moon, but what about my Earth?"

So basically the game gives me no option once so ever to change my earth...
Could I have a little help please, and guidance?

I think you should press the R3 button to switch from Moon to Earth.

Yeah. What jhonsiak says. They removed aditional Decorate Button and My Pins has moved in its place.

Thanks .