precocious

Concise Oxford English Dictionary © 2008 Oxford University Press:
precocious /prɪˈkəʊʃəs/

▶adjective

• 1 having developed certain abilities or inclinations at an earlier age than usual.

• 2 (of a plant) flowering or fruiting earlier than usual.

– derivatives
precociously adverb,
precociousness noun,
precocity noun.

– origin C17: from L. praecox, praecoc- (from praecoquere ‘ripen fully’, from prae ‘before’ + coquere ‘to cook’) + -ious.