Juvenile/YA Fiction Angels

I am looking for a book I read in the early to mid 1990s. It takes place during the summer, involves two groups of adolescent girls, and one girl wanting to learn ballet because she thinks that's how angels dance. She (I forgot her name) and her group of friends can actually see angels, and during the summer they meet a woman and her son and daughter (fraternal twins) who live in the woods and are home schooled. The book also deals with dieting. The book ends at a summer fair/carnival where bluegrass music is played and the girl and angels dance to it.

I’m not sure if this helps but could it maybe be the Forever Angels book series, this specific book may be Christina’s Dancing Angel?