How can I make my room more grown up?

It is lime green and blue. I don't want to get rid of all my stuffed animals and such but I don't want them to be a focal point. I am not aloud to paint again but I like the colours so that's okay. I have a wooden loft but could change it into a twin sized bed. My dresser is wooden and it was my aunts so I don't want to get rid of it. I have a desk that my dad made me.