If you join it under 50 you get what's called an associate membership. But only one person have a couple needs to be over 50 to join.

There's also confusion hear about joining AARP versus an AARP rate. We've never been asked to show age proof or AARP cards one claiming this rate, but I'm guessing at some very uptight hotels my question you if you look under 40 and produce an AARP rate. No personal experience, but just guessing that it might occasionally happen.