Hello and sorry for the late reply. Hope I’m not too late and you didn’t already finished decorating your room….^^
For the best overall result, stay away from extremely pastel colors„like light pink and pastel yellows, but these colors can look more childish and washed out. If you want your room to look attractive and mature, look for shades of brown, turquoise, deep purple, or dark red. These colors still look feminine, trendy, and stylish, but they will add a richer and more vibrant tone to a girl’s room.
The best choice for a bedroom wall for a teenage girl’s room is a muted jewel tone. These soft color shades would include: mocha, amber, turquoise, amethyst, and ruby. It is important that these color tones stay on the lighter side, because dark walls will inevitably shrink the room.
A mature and feminine touch to the room would be to mount an ornate mirror. These can often be purchased for a very reasonable price, and you can always paint the frame around the mirror in a silver metallic finish.