Maturity is the state of complete physical growth and development. By the age of 18-20 years, complete physical maturity must have taken place.
However, there is this other part of maturity which is emotional and mental. This the ability to appropriately respond to your environment like an adult both mentally and emotionally.
It is expected that emotional and mental maturity grow as one grows older. Nevertheless, it is not always so. This is because you can still find someone at age 30 who would respond to certain situations like a 17-year-old would thus showing emotional and mental immaturity. It is also possible for a 23-year-old to be more mentally and emotionally mature than a 30-year-old. It all depends on the individual involved.
Age might not be a good yardstick to measure one’s emotional and mental maturity. After all, age is only a number.
Princeton Hines