You could go to the fragrance counter at a department store and tell them the age of your niece and what type of fragrance you are thinking of. They will help you find suitable ideas. There are MANY fragrances out there that are geared towards young women/teens.

Once you find something...you could put together a package...many offer soap, body wash, lotion, cream (thicker and heavier than lotion), powder, deodorant...in addition to the perfume.