Get married early while you have not had a stable career and two people can not take care of themselves and their children anymore, which makes them a burden to society. So get married when you are financially secure
Marrying when you are not ready is never a good idea, and it is obvious that the younger that you are the more difficult it is going to be for you to be ready for such a big responsibility, there are some that are able to pull it off and can make their marriage a success but the majority of people that are not ready will fail because the responsibilities that you need to face can be too much for some people to bear.