I started getting these from AARP a loooong time before I turned 50 and I was really insulted! My brother, on the other hand, jumped all over it for the discounts. He traveled a lot and liked the discount on hotels. They probably do make the starting age so low to attract a larger membership. I'm 61 now and certainly don't consider myself a "senior citizen". I'm more like my aunt who is 85 and still volunteers to deliver Meals on Wheels to "the old people"! I figure that "old" is anybody who is at least ten years older than I am! I also get things in the mail all the time from the hearing aid companies.
When I first started working for the State, I was forty and not too thrilled about it either. And almost immediately, I started getting notices about "retirement seminars" and Social Security workshops! WTH? Our personnel lady (who is the same age as me) finally figured it out through. In my personnel records, I somehow ended up with somebody elses birthday! Not just the year wrong, but the month and day too!