Alma Deutscher's own take on Cinderella involves a poet prince being charmed by the melody of a female composer, rather than the singing of her pretentious two half-sisters.
The characters are played by adults, with Alma accompanying them on the violin in some scenes. Thursday evening's premiere at the city's Casino Baumgarten Concert Hall was packed.
"I am extremely proud. If anybody had told me a few years ago that my opera would be put on in Vienna, I'd have thought it was a joke," she told BBC Radio 4's Today programme.
The production also has an adult director but Deutscher said in the interview she often passes on her own ideas about how the opera should play out.
"It's all coming together," said Deutscher, who is home-schooled and lives in south London, noting that she still takes her skipping rope to rehearsals, using it during breaks.
The opera will be performed again in Vienna on Friday as well as on January 4 and January 5.
The conductors Daniel Barenboim, Zubin Mehta and Simon Rattle have spoken glowingly about Deutscher's talent.
"Last night's premiere played to a packed house of 540 and at the end there was a standing ovation with many shouts of bravo!" the prodigy's publicist Judy Grahame said in a statement to AFP.
"Alma was so happy to see the performance which for so long had lived on her imagination."