precocious -
characterized by or characteristic of exceptionally early development or maturity (especially in mental aptitude); "a precocious child"; "a precocious achievement"
retarded relatively slow in mental or emotional or physical development; "providing a secure and sometimes happy life for the retarded"
intelligent having the capacity for thought and reason especially to a high degree; "is there intelligent life in the universe?"; "an intelligent question"
precocious -
appearing or developing early; "precocious flowers appear before the leaves as in some species of magnolias"
early at or near the beginning of a period of time or course of events or before the usual or expected time; "early morning"; "an early warning"; "early diagnosis"; "an early death"; "took early retirement"; "an early spring"; "early varieties of peas and tomatoes mature before most standard varieties"
