少年老成 Precocious maturity
Explanation
形容年纪虽轻，却很老练稳重。现在也指年轻人缺乏朝气，显得过于老成持重，少了青春活力。
Describes someone who is very mature and composed despite their young age. Now it also refers to young people who lack vitality and appear overly mature and serious, lacking youthful energy.
Origin Story
话说汉朝时期，有个叫韦元将的少年，十五岁时就已经做了郡主簿，处理政务十分得体，令人赞叹。杨彪见到他后，不禁夸赞道：“韦主簿年纪虽轻，却已有老成之风，真如同千里马般前途无量啊！”韦元将少年老成的事迹，成为后世人们称赞的典范，也让“少年老成”一词流传至今。这故事告诉我们，虽然年龄并非决定一个人成熟与否的关键因素，但拥有超越年龄的成熟和责任感，同样令人敬佩。
In the Han Dynasty, there was a young man named Wei Yuanjiang who, at the age of fifteen, became a county magistrate and handled government affairs very well, which was admirable. When Yang Biao met him, he couldn't help but praise him: "Although Wei Yuanjiang is young, he already has the bearing of a mature man, like a steed capable of running thousands of miles!" Wei Yuanjiang's story of precocious maturity became an example of praise for later generations, and the term "precocious maturity" has been passed down to this day. This story tells us that while age is not the key factor in determining maturity, the possession of a maturity and sense of responsibility beyond one's years is equally admirable.
Usage
用于形容年轻人成熟稳重，或指年轻人缺乏朝气，显得过于老成。
Used to describe young people who are mature and composed, or to indicate that young people lack vitality and appear overly mature.
Examples
-
他年纪轻轻，却少年老成，处理事情非常老练。
tā niánjì qīngqīng, què shàonián lǎo chéng, chǔlǐ shìqíng fēicháng lǎoliàn
He is young, but he is already very mature and handles things very skillfully.
-
小明少年老成，不像同龄孩子那样幼稚。
xiǎo míng shàonián lǎo chéng, bù xiàng tónglíng háizi nà yàng yòuzhì
Xiaoming is unusually mature for his age and not as naive as other children.
-
会议上，他少年老成地提出了建设性意见。
huìyì shàng, tā shàonián lǎo chéng de tí chū le jiànshè xìng yìjiàn
At the meeting, he put forward constructive suggestions in a mature and thoughtful way.