LW1 - She can respond to "Are you hiking with your mother?" with, "No, she's a friend and is one year younger than me." BOOM! But Amy's suggestion of responding to questions with "Why do you ask?" is SOOOO lame and worthless. If the curious "rude" person is asked this, they will answer why they want to know, and then wait for the answer to their question. I've asked "old" people in the gym who had fantastic physiques how old they are. Every single one of them seemed delighted to tell me and gloated in it. The hiker is being a bit over sensitive, though the assumption by other hikers that her friend is her mother doesn't exactly show a high IQ, either.