The bubonic plague was a painful disease, with black buboes, or swellings, in the groin and armpits, which lasted up to a week. There was some chance of surviving if the buboes burst.
As of 2015, full retirement age is 67 if you were born after 1960. The amount you receive doesn't change because disability benefits were calculated based on what you would receive at retirement age. However, you may see an increase if Social Security provides a cost of living increase.
However, collecting Social Security retirement early rather than applying for disability has drawbacks that should be considered before making this decision. If you take early retirement once you reach the age of 62, your retirement benefit amount will be permanently reduced.