at one's age

基本解释

I have my understanding of being independent at 30, that is, having a career at this age and following one's own ideas.
我对三十而立的理解是：三十岁时，需要有一个职业，可以让自己的思想驰骋。
blog.sina.com.cn
Habit is cultivated gradually and it is easiest to cultivate habit at one's young age. Once a habit is cultivated, it is difficult for you to change it.
习惯是慢慢养成的，在幼小的时候最容易养成，一旦养成之后想改变过来却还不很容易。
Standing at the helm of one of the computer age's biggest success stories while its brand withers and its stock languishes at the same level it traded at in 1998.
他执掌的这家传奇性的公司曾是计算机时代最成功的公司，如今却面临着品牌日益畏缩，股票不断贬值的窘境，其股票的交易已经回落到1998年的水平。

And one of the reasons that's most responsible for that is that humans aren't dying at as young an age from infectious diseases as they did three or four hundred years ago.
最重要的一个原因就是,人们不会在年轻的时候死于传染性疾病,而这在三四百年前确实会发生
耶鲁公开课 - 生物医学工程探索课程节选
What I found when I thought about the Methuselah case was, even though it was me at age 800, the same person as the one who's standing here in front of you now, ?" it didn't really matter. I said, "So what?"
当我思考Methuselah时，我想到的是，虽然八百岁时的我还是我，和现在站在你们面前的人,是同一个人，那已经无关紧张，我说了“那又怎样“
耶鲁公开课 - 死亡课程节选

What he means is that at age 59, he's got one last chance to leave his mark.
FORBES: Paper Chase
Chris Kelly, half of the 1990s kid rap duo who made "Jump" one of the decade's most memorable songs, died in Atlanta at age 34.
NPR: 10 Things To Know For Today