child prodigy
From Longman Dictionary of Contemporary Englishchild prodigyˌchild ˈprodigy noun [countable] INTELLIGENTGOOD ATa child who is unusually skilful at doing something such as playing a musical instrumentExamples from the Corpuschild prodigy• A wonderful, uplifting movie about a child prodigy who is damaged, then saved, by his art.• As the book opens she is turning this demanding four-year-old into a child prodigy.• I was something of a child prodigy.• Evgeny Kissin was the kind of child prodigy who made people believe in the possibility of a Mozart.