This question is relatively sensitive, and there are many ways to ask it, but they all have one characteristic, which is to be tactful and go in circles. When you are having a very interesting conversation with a girl, you suddenly change the subject and say: "I am 26 years old. It seems to me that you are three years younger than me, right?"
When you say this, you must keep your eyes focused. Look at the girl's facial expression. If her face turns red, it means your words are correct.
I am a shrimp, what are you?! Miss, you look very young, you must be less than twenty. If you look at a girl who is about 23 years old, you can be very surprised and say, are you 20 this year? She might retort, "Who said that? I'm already 23, or not... If I glare at you, I'm definitely younger than 20. If my eyes are slits when I smile, I'm definitely older than that. That's okay at this time." Keep asking!
Ask her in which year she started working (in which year she graduated, in which year she went to middle school, etc., you can calculate it yourself). When inviting her to dinner, say: You must be a dog. The beauty looked surprised and asked: Why? I see you are very skilled at eating bones. Do people born in the year of Tiger have no skills? Combined, these methods are: deduction method, provocation method, and surprise method.
:)