Sorry to inform you but it is definitely NOT "age discrimination" as that case was already taken to the U.S. Supreme Court and they ruled that the 'Age 60 Rule' was NOT age discrimination. Unless you want to take a case all the way to the Supreme Court and get them to 'overturn' their previous ruling it is NOT age discrimination.
Also, I guess that it is also 'age disrimination' that ATC controllers are 'required' to retire at age 55; or the 'fact' that no one over the age of 38 yrs old can apply and be hired as a 'Sky Marshall' and so on and so.........
Again, Age 60 is NOT Age Discrimination.
Hope that makes it clear for you.
DA