Realm of the Elemental Witch Series by Lenore Wolfe

My name is Cillia, and I am a Fire Sprite. I try to help kids who run away, but to see me--they have to remember how to believe…. Alli's mother is dead. And there are certain old meddlers in their small town who don't believe her stepfather, a black man, should raise a 15-year-old white girl. On top of it, if the old busybodies knew that Alli was seeing Faery creatures, they would probably put her away anyway. So she decides to run away. But a Fire Sprite takes her to the Land of the Fae.