Agneza, I'm in love with that attic and I don't thing there is anything that should be changed. Ceiling is fitting perfectly, and it's great you playtested it and everything seems to be functional as well! Simply adorable place!
Vampire, that bedroom is huge and I would divide space in 3 uneven spaces, one small as entrance hall, place to read a book near the window, with lemonade or something, or a bar, or easel/artist room or whatever your sim likes to do. Second small one in the corner can be a closet as Gogo suggested, and you'll still have large bedroom area where the bed is now. I like the colors and what you did to the pattern on walls, but the space is huge and I would be puzzled what to do with it too!