rareripe

adj

1. (not-comparable)ripening early (said most commonly of peaches and onions)
2. (broadly, not-comparable, uncommon)maturing too quickly; taking on the trappings of maturity before one is emotionally developed

   “He is quite smart enough. I sometimes fear that he is one of the little rare-ripe sort that are smarter at about five than ever after.”

noun

1. An agricultural plant that ripens early.