People who experience a delayed heyday in their 20s and/or 30s, when they finally have the factors (social and/or job status, money, body, looks, etc.) to get laid and gain attraction/popularity among the opposite sex. These people were typically categorized as nerds/geeks back in high school.

a teenager of ages 16-18 who is still in the early phases of Puberty

referred to someone who develops a skill later than usual. usually referred to a player who signs a contract in his early twenties in association football.

When a girl hits puberty later than everyone else

a nice way of saying someone is mentally slow on learning new things.

A fart that is passed but does not smell right away. A surprise attack, a mystery.

Late Bloomer Bride is a term that means a woman who married for the first time after age 40.