precocious

Manifesting or characterized by development, aptitude, or interests considered advanced for a given age.

Blossoming before the appearance of leaves.

In biology, present in an egg or embryo at a very early stage in an imperceptible condition; present before becoming manifest.

Noting birds that, like chickens, are able to run about as soon as hatched; precocial. See Præcoces.

Ripe before the natural time.