https://thewoksoflife.com/chinese-birthday-traditions/

In the old days, if you were to ask a Chinese person’s age, they would gladly tell you. But these days, Chinese folks are influenced more and more by Western culture, so don’t be surprised if people try to dodge the age question—especially women! 

But if you must ask, here is how to ask a Chinese person their age:

• When asking children: “你几岁了?” (Nǐ jǐ suìle?) This is usually a friendly question, asked with a big smile! 

• When asking a young to middle aged person, “请问您贵庚?” Qǐngwèn nín guìgēng？ This phrasing is more polite than what you might ask a child. 

• When asking a young to middle aged woman, you can also use, “请问您芳龄?” Qǐngwèn nín fānglíng? Again, this is polite phrasing, but just know that she may politely decline to answer. 

• When asking the elderly (both men and women), “请问您高寿?” Qǐngwèn nín gāoshòu? Again, a big smile never hurts. 

There are also different customs for youths and for elderly folks, and so there are different terminologies for how to refer to “celebrating your birthday.”

For children and people up to middle age, to celebrate a birthday is: 过生日 (guò shēngrì). 

For elders, to celebrate a birthday is: 做寿 (zuòshòu). Folks who are attending a birthday party are coming to 贺寿 (hè shòu) and 祝寿 (zhùshòu). 

And you shouldn’t use the term “做寿” lightly. Most people would not use this word on themselves unless they consider themselves “too old,” which is subjective. It’s best not to use it with anyone younger than 80 years old! 

You will likely get more than one answer. For example: The person being asked might say something like, my nominal age (虚岁 – xūsuì) is 63, but my real age (实岁 – shí suì) is 61.

Confused? Here’s how they work: 

• Your real age (实岁, shí suì) is based on your birthday, as in Western culture. You’re 1 year old on your first birthday, and another year old on subsequent birthdays. 

• Your nominal age (虚岁, xūsuì) is based on Chinese tradition. You are 1 year old on the day you are born, and on the very next Chinese New Year, you are another year old. This is why some people might have a 2-year gap between the two ages.

Also, in China, people may still have the habit of following the lunisolar calendar, instead of the Gregorian calendar. In these cases, birthdays vary yearly. For example, Chinese New Year Day changes year to year on the Gregorian calendar, but it’s always the first day of the first lunar month on the lunisolar calendar.