Age Difference Between A Man And Woman In Marriage? Does It Really Matter?

Does it really matter if a man is younger than a woman in a relationship/ marriage? What are the effects? Do such marriages last? In Nigeria generally, people are of the opinion that the man must be older than woman. I once heard that psychologically, a man is on the same level of reasoning as a woman who is about three (3) years younger than he is. Is this true?