As a general answer: As far as I know, there is currently no exact scientific method to measure and determine the age of a person.
Certain techniques can give more or less rough estimates, however a precise technique that works for all age groups is tricky.
The following article is from 2014, but gives a good glance at several existing methods and directions of research.
https://www.vox.com/2014/10/20/6939271/age-test-aging-epigen...
It should be noted, that many techniques in this area are invasive, requiring blood/tissue sampling and/or exposing a person to ionizing radiation (XRays), which makes them prohibitive in many scenarios.
As a general answer: As far as I know, there is currently no exact scientific method to measure and determine the age of a person.
Certain techniques can give more or less rough estimates, however a precise technique that works for all age groups is tricky.
The following article is from 2014, but gives a good glance at several existing methods and directions of research.
https://www.vox.com/2014/10/20/6939271/age-test-aging-epigen...
It should be noted, that many techniques in this area are invasive, requiring blood/tissue sampling and/or exposing a person to ionizing radiation (XRays), which makes them prohibitive in many scenarios.