A Wunderkind, composed of the German wunder (‘wonder’) and kind (‘child’), is a prodigy, or person who succeeds in a difficult field at an early age.
Since Wunderkind is capitalized in its native German, keep it capitalized–it’s more snobby that way.
Plural: Wunderkinder (VOON´-der-kin´-der)
My little brother is a Wunderkind. He’s only sixteen years old, but he’s already graduated from Harvard and running his own company.