He is thirty (years old).
He is thirty years of age.
He is already thirty.
He has reached the age of thirty.
a thirty-year-old man
a man who is thirty
a man of thirty
a man aged thirty
a man at the age of thirty
He is nearly thirty.
He is close to thirty./He is toward thirty.
He is getting on thirty.
He is pushing thirty.
He is well over thirty.
He is thirty something.
He is as old as I am.
He is as old as me.
1.她看上去比实际年龄小：She looks younger than her years.
2.她看上去比实际年龄小十岁：She looks ten years younger than her real age.
3.我年纪比你大：I am older than you.
e.g. I appreciate that. Speaking of which, I was wondering if I am older than you, because you look so young.
4.她三十岁了，但看上去才二十岁：She is thirty but looks twenty.
e.g. She is thirty but she appears young.
1.一个未成年人：an underaged / a teenager/ a juveniles/ an adolescent/ a minor
2.一个成年人：a grown-up/ an adult/ a person of mature years
3.一个中年人：a middle-aged man/ a man of middle age/a woman of certain age
4.一位老人：an elderly man/ an aged man/ a man in his old age