The book is juvenile fiction about a young girl, age 9, who dances ballet.  She wants to start using toe shoes but everyone tells her she is too young.  She goes on a summer vacation to the beach and meets a famous ballerina and her choreographer husband who decide to stage a shortened version of The Nutcracker at the grand hotel where they are staying.  The girl is invited to participate even though she is not staying there.  The owner’s spoiled daughter makes a fuss and is cast as Clara.  She had started dancing with toe shoes but it is causing too much stress on her developing feet and she can’t dance very well.  I think her name is April.