It is improper to ask someone how old they are. It is also improper to ask others to guess your age.
If you find yourself in the dilemma of guessing a person’s age, it is politically correct to subtract at least five years from the age you believe them to be.
If you are asked by a teenager to guess their age, add one or two years.
If a child under ten asks you to guess their age, you better be right on. They are all about exactness.