I would agree with this as it maps to my personal experience:
Are You as Old as You Feel?
Are You as Old as You Feel?
Terracciano and colleagues have found that subjective age correlates with certain physiological markers of aging, such as grip strength, walking speed, lung capacity, and even the levels of C-reactive protein in the blood, an indication of inflammation in the body. The younger you feel you are, the better are these indicators of age and health: You walk faster, have better grip strength and lung capacity, and less inflammation.
...the message seems to be that our chronological age really is just a number. “If people think that because they are getting older they cannot do things, or cut their social ties, or incorporate this negative view which limits their life, that can be really detrimental,” says Terracciano. “Fighting those negative attitudes, challenging yourself, keeping an open mind, being engaged socially, can absolutely have a positive impact.”