A pubescent girl or boy has reached the stage in their life when their body is becoming physically like an adult's.
例句
...a horde of pubescent boys and girls who tug at his microphone.拽扯他的麦克风的一群少男少女
英英词典释义
Adjective
1. (of animals especially human beings) having arrived at the onset of puberty (the age at which sex glands become functional) but not yet fully mature;
"the budding breasts of a pubescent girl and the downy chin of pubescent boy"