I got certain senior citizen benefits at the first tier, age 55 (like senior admission to the movies, McDonalds' coffee), and at the second tier, age 62, I get others (senior discount on Long each buses). I've heard there is a third tier at age 65 and possibly another at 70... IF I make it that far!
Pretty sure at 70 - you are assigned a sherpa to carry your gear - so hang in there!