"Traditionally, the full benefit age was 65, and early retirement benefits were first available at age 62, with a permanent reduction to 80 percent of the full benefit amount. Currently, the full benefit age is 66 for people born in 1943-1954, and it will gradually rise to 67 for those born in 1960 or later."(nasi.org)
This is a true fact, if the age is going to rise to 67 it will keep rising after that. Retirement is supposed to let you enjoy your life after years of working, but let's be honest how much could you really enjoy life at 70 years old. If the age is changed to 57 it also gives grandparents time to spend making memories with their families and will let a older person truly enjoy the quality of life the way retirement is supposed to.