Tell an opera impresario to pull together a professional production of a new work in six months, and they’ll laugh. Tell them to do so for a score written by a 12-year-old, and they’ll probably start questioning your sanity. Somehow, Opera San Jose and the Packard Humanities Institute have managed the impossible. Precocious composer Alma Deutscher has expanded her Cinderella for its first, full-scale staging, which comes complete with a 44-piece orchestra, renowned conductor Jane Glover, lavish sets and costumes, and a young and talented cast. Cinderella isn’t without its flaws, but it illustrates its composer’s prodigious gift.

Deutscher has repeatedly said that she prizes beauty in music. Cinderella is indeed pretty in a traditionally melodic way. A good sign for Deutscher’s future as a writer of opera: Her best musical ideas encompass a variety of characters and moods. The stepsisters get charming, frivolous duets and ariosos full of trills and ornaments. (They are opera singers, after all!) This self-consciously operatic music is both funny and well-executed. Similarly, the Stepmother sings a thrilling short aria (“I must get rid of her”) with clear references to “Der Hölle Rache” (from Mozart’s Magic Flute) in both affect and stratospheric top notes.