Notice that Senate wasn't the only governing party in ancient Rome. Also "old" is relative. It meant "too old to serve in military", with Sulla's reforms the minimum age was 31 and even before that most influential senators were 40-50.
For emperors: out of 80 only 14 were over 65. 2 resigned/died at 66, 1 at 67, 2 ruled only few months, so really 9 out of 80. Rome is not the place to look for old rulers
For emperors: out of 80 only 14 were over 65. 2 resigned/died at 66, 1 at 67, 2 ruled only few months, so really 9 out of 80. Rome is not the place to look for old rulers