My father lived longer than his mother, father, and seven brothers. He was 78 when he died.
My mother outlived her father, four brothers and one sister (probably shouldn't count her, as she was murdered). Two younger sisters are all that remains of her family. Mom was 74 when she died.
I have already lived longer than many of my uncles and both of my grandfathers. Hell, the uncle for whom I was named died of heart disease when he was 34 (two years before I was born).
So I'm not holding out much hope for becoming a centenarian.