Precocity; maturing earlier than usual — applied to people (e.g., emotionally or intellectually precocious children) or to plants/fruit that ripen early.
彼は数学に早熟で、小学生の頃から大学の教科書を読んでいた。
He was precocious in math and read university textbooks since elementary school.
この品種は早熟なので、例年より一週間ほど早く収穫できる。
This variety ripens early, so it can be harvested about a week earlier than usual.
妹は大人びていて早熟だと言われることがあるが、まだ子どもらしいところも多い。
My younger sister is sometimes called precocious because she seems mature, but she still has many childlike aspects.