How old was Mozart when he first performed musically?

Wolfgang Amadeus Mozart was a child prodigy who at three played harmonies on harpsichord, wrote minuets at five, and performed on tour at six. He played any keyboard or string instrument without training and achieved fame on piano in 1778, at twenty-one. He was a virtuoso and composer well-known in Europe who made a lot of money before he died at thirty-six.