In our generation, people are not marrying in their teens as prominently as in previous generations. The obvious conclusion drawn from our history is that marriage age has consistently increased as our society has aged. The obvious result from this trend is that humans now are faced with a more challenging task of staying pure before marriage. Marriage has been continually set for a later age because of clear reasons. One of which is the beautiful institution we are a part of right now.
Universities promote belated marriages.
It just makes sense to marry after you have gotten a degree and are on your own. Our evolution in age of marriage has not been met with the same evolution in puberty. Puberty is not occurring later in humans today than 2000 years ago. Previous generations had it easier. They didn't have to wait as long for sex ,because they were married at younger ages.