The phrase "How old is she?" is a common English question used to ask about a female person's age. The specific age referred to by "she" depends on the context, as it is a generic question without details about who "she" is. For example, in some teaching materials or songs, "she" might be described as twenty years old or other ages depending on the narrative context. Without additional context, it cannot be determined how old "she" is exactly.

If there is a particular person in mind, please provide more details or specify the individual so an accurate age can be given.