The "chronological age" is the actual age that the individual is, it is the measure of the person's life in years, the life span of the person after birth. For example: a baby born on April 10 will be 3 months old chronologically on July 10.
Biological age refers to the quality of health, how old the person appears to be. Social age refers to the assessment of the degree of suitability of an individual to the performance of social roles and behaviors expected for people of his age at a given time in history. Finally, mental age refers to individuals who behave differently from the standard for their chronological age. In this sense, a 15 year old man who has the maturity of an adult is considered as someone with a more advanced mental age
