How old are you? I’m twenty-five years old. How old is he? / How old is she? He is five years old. / She is five years old. He is old. / She is old He is young. / She is young.

How old are you?
I’m twenty-five years old.
How old is he? / How old is she? 
He is five years old. / She is five years old.
He is old. / She is old
He is young. / She is young.