google says best age for marriage is between 28 to 32. but I think marriage is a private affair, and there is no fixed rules on it, it depends pretty much on who you are as a person. your economic, cultural and educational background plays important role in this process. take my country as an example; generally rural people marry younger and are happy with their life, but in the metropolitan areas circumstances differ vastly, a well paying job, a house and a car are minimum requirements of marriage process, then probably you need higher education for a well paying job, the result will be huge increase in marriage age .from a personal point of view marriage in old age would be better choice; you have more time to have a better understanding of yourself, who you are and what do you want out of life, who is the best match for you and what do you want out of marriage.
I think it depends on the level of awareness and responsibility they should reach to be able to get married and raise a child .
If there was some the mistakes in my speech please tell me about it and correct to me if you don't mind certainly and thanks all .
However, young people less than 20 can be a very high risk for a poor marriage chiefly due to lacking of experience in dealing with difficulty in many ways and they usually have to struggle among their career, family, education ...etc to survive so supposedly more difficult to maintain an independent family on their own.
