How to make my bedroom cute/kawaii?

Well im gonna be real with you, if your 21 and under, OF COURSE! it all sounds cute, you should get baby colors(pink, blue, peach, etc..) but if your 21 and UP, your just a big goofy, why would a grown woman/man still have a big fat hello kitty face plastered on their wall, or a big fat poke' ball? im not trying to get everyone to thumbs me up, but im just telling the truth, and for all you people out there mad at me for saying that, you just have to grow up :)