Given the way we were created, I think it is in everyone's nature to want to get married. However, it isn't necessarily in everyone's nature to want to get married within the first hundred years of their life. Looking at the first five chapters of Genesis, you find that many people were of ages in three digits before having their first child, which suggests that either they weren't very fertile (which isn't what you'd expect for perfection) or they were content to wait a while to get married. So while getting married is part of Jehovah's design for us, it may well be true that getting married in your twenties or younger is more of, as you put it, an educated need.
As you acknowledge, God chose this manner of reproduction. Not all creatures reproduce in the same fashion. Flowers engage in sexual reproduction but without having two different sexes - each individual has both male and female organs, and God could have made us the same way, hermaphroditic, with no differences between us. Some other creatures reproduce just by cloning themselves, without even needing another organism, and God could have made Adam that way. But Jehovah saw fit to make a man and a woman as complements of each other, even though this was not strictly necessary to allow the earth to be filled. Jesus explicitly said he made them male and female and said for this reason a man would leave his father and his mother and would stick to his wife, and the two would become one flesh. It seems to me that this is why men and women exist - not merely to reproduce, but to marry, to complement each other's unique abilities. For this reason, I believe all people will eventually marry if they live long enough.