One of my students asked me why I am thinking about retiring so I told her "Because I am old." She looked at me and said, "No, you're not. How old are you anyway? You can tell me, I won't tell anyone." With a straight face, I said "75 and I should have retired 20 years ago." Instead of calling me on this number, she said, "Damn, you look good. You are in better shape than my mom and she is only 50." We continued doing math and let the topic drop.
This girl, who promised to keep my age a secret, walked into class later on and said to everyone, "Would you believe she is 75? Doesn't she look great?" A few kids tried to correct her but most of the other ones jumped in and agreed that I don't look nearly that old.
Moral of the story: Go get your senior citizen discounts early, especially if a teen is taking the money. They don't know the difference between 40 or 50 or 80.