Chronological age
\ˌkrɑnəˈlɑʤɪkəl\ \eɪʤ\
Chronological age is age measured as time elapsed since the date of birth.
Hence the chronological age on 1 January 2019 for someone born on 1 January 1969 would be 50 years. Due to lifestyle, environmental and genetic effects two people of the same chronological age, may appear to have aged very differently.