In addressing the question of when is the right time to get married, various factors need to be taken into account.

When societies were largely agrarian, people lived in extended families and communes. Couples had extended support from their extended families and communities. Moreover, labor was a major consideration is such societies and children provided the much needed support here. In some such societies life expectancy was very low - in some societies it was as low as 30. Therefore, given these factors, it was necessary (and in fact there was an urgency) in such societies for people to get married as soon as possible.

As time progressed, with the advent of industrialization and the attendant proliferation of towns and cities, the extended family and communal living style gave way to nuclear families. People started living away from their parents and communes in towns and cities. This created new physical, mental, emotional and spiritual demands on couples. Moreover life expectancies of people have improved much overall. Tertiary education became common place. A combination of all these factors meant that it became necessary for people to wait until they were deemed somewhat ready to start a nuclear family before getting married. Getting married earlier, as in an agrarian society, wasn't an option as they didn't have the support of an extended family or community in place.

In addition to the above factors, how a person or the society he/she lives in views the purpose of marriage also influences the right time to get married. The chief purpose of getting married can be divided into several categories:

1. Physical, Mental and Emotional Wellbeing.
People who subscribe to this category would consider the chief purpose of marriage to be Sexual pleasure only, or Procreation for the propagation of family lineage or Fellowship, companionship, mutual help and comfort.

2. Utilitarian.
People who subscribe to this category would consider the chief purpose of marriage to be procreation as insurance for support at old age or to have financial security or to retain family wealth within designated families.

3. Religious Duties.
People who subscribe to this category would consider the chief purpose of marriage to be fulfillment of religious duties.

4. Spiritual.
People who subscribe to this category would consider the chief purpose of marriage is to grow in selflessness by loving your spouse and his/her family as your own first through the institution of marriage, which then becomes the stepping stone to love everyone else later.

Which of the above categories a person or society subscribes to would also have an effect on the time of marriage.

By now, you will realize that there is no straight answer for your question. It largely depends on the individual and societal beliefs and aspirations prevailing at the time and space the individual lives in.