Because I've met quite a few teenagers who think they know it all. Given similar/normal circumstances, how do you as an 18 year old think you know more about life and life's experiences than say someone my age (36) or older? Given normal circumstances, a teenager is never going to be as mature as someone in their 30s or older. Why do you think that most(normal, sane minded) people don't date someone that is over a decade younger/older than them; because of the time during their life that they are at, and the maturity level. Granted there are exceptions but I would normally not date a woman younger than 23 or 24; because of the maturity level, and the difference of where the girl is in her life and where I am in mine. I even had that mentality for a little while when I was a teenager. Over the past two decades, I've come to realize exactly what little I did know.