a whizz-kid

whiz kid

A person, usually a child or young adult, who is exceptionally skilled or intelligent. He was developing software by the time he was 10 years old—he's a total computer whiz kid. Those whiz kids at the spelling bee are always so impressive to watch. Sarah's the new whiz kid in accounting. She'll help you tackle the budget in no time.
See also: kid, whiz
Farlex Dictionary of Idioms.

a ˈwhizz-kid

(also ˈwhiz-kid) (informal) a person who is very good and successful at something, especially at a young age: ‘Who’s the new manager?’ ‘A financial whizz-kid from Harvard Business School.’
Farlex Partner Idioms Dictionary
See also:
  • (as) mean as a junkyard dog
  • a whale of a
  • tech-nerd
  • media darling
  • (as) cross as a bear
  • OL
  • big ol'
  • big ole
  • olé
  • the bigger they come/are, the harder they fall
References in periodicals archive
I've just learned to use the computer, I'm a whizz-kid at downloading e-mail.
Daily Poem; SENIOR SURFING
One such 'expert' is Danny Baker, a has-been who has never been, a was- kid without ever being a whizz-kid.
FOOTBALL: USE YER LOAF BAKER; Do us all a favour and stop talking rubbish
But he doesn't need a whizz-kid economist to tell him to stay away from that dangerous merry-go-round.
Pay up, Bertie
TRAGIC tot Chloe Nolan has escaped from a secret world of torment - by becoming a whizz-kid on computers.
TRAGIC COMPUTER KID CHLOE, 5, FINDS LOVE AT FIRST BYTE