There is no proper answer to your question because there is no best age to get marriage because various things people keep in their mind that when they have to marriage and the thoughts what they have in their mind behind the marriage.
Some people thinks that the best age is 22 because the people who are illiterate they do marriage at this age but why it is not proper age .if the person is literate and he wants to go abroad for further study then he will surely do marriage after the age of 26-28 because he had so.e ideas that when he had money in his hand then only he is capable to to take the responsibility of the family.
Other people likes doctors ,engineers are feels that after their education is finished and do PhD and many more then they would marriage because they had got a good job and earning also coming at their home and they will marriage after the age of 28 because minimum it takes 28 years to reach this level.
So,the best age to get marriage is depended on the people in which categories they are coming.and also what thoughts they have or what aim they have to do plan for marriage.