I recently checked out Pottery Barn Teen for the first time and was pleasantly surprised! I'd never thought to look through their products before because I do not have any teens and am not a teen myself, but found a few items that appealed to my adult self. The stuff is youthful, fun, and cheery. While I'd recommend going more neutral with larger pieces, such as sofas, etc. (because you'll get more years out of them), it's totally OK to play around with bright accents like pillows.
De-Vine Pillow Cover
Zig-Zag Pillow Cover
Tulips Toss Pillow