This is a serious issue on many levels that crosses the boarders of the "peer pressure", "understanding", "modern thinking", and "neglect from parents".
I'll break it down as best as I can. I take it most people in this thread are males, so I can't speak for females.
You know how tough it was between 13-18. LOL. The thoughts were almost constant and almost uncontrollable. It was a strange and confusing time basically stuck in a paradigm of "being a kid to society", when in reality 300 years ago we'd have no problem surviving on our own if we had proper instruction on living, planting, animals, and surviving. Instead most of us were in classrooms with our minds nearly restless. Most of us were highly independent and felt trapped in our lives because we were still at our parents home with no opportunities (because 18 is the magic adult age) for real work.
The way that God made us was at those ages to be extremely fertile and ready to start life with a female in Holy Matrimony. Like I said in a previous post, the virgin Mary is highly speculated to be around 14-15 when she gave birth to our God and savior. But to think of anybody in the USA getting married at 14-15 is seriously considered horrendous. People would be all over that calling it "child abuse". Many states even have laws stating "nobody under 16-17" depending on the state will be granted a "marriage license".
School systems suppress life experience of the young ones and fill their minds with stories such as "The Raven" (murder), "Romeo & Juliet" (teen suicide), and Beowulf (sorcery & witchcraft), (side note: and don't allow prayer) and basically tell young adults that they graduate around 18 years old.
The government who is funded by us, funds the school system. 18 again is the "magic age" to be an adult. Barely any jobs under 18 pay anything and it basically suppresses young adults from starting their lives.
I guess my point is, just because WE have always seen things this way or that way, doesn't mean it's right.
Parents also neglect life lessons to their children and they are virtually unprepared at 18 to face the world. Why? The school system raised them.
Now days, 25 seems too young to marry.
So people fall into all kinds of sins. (Let's face it monks make up a teeny weeny fraction of the world's population).
For most people the influence is too strong.
Couple that with a moral disaster that comes through the T.V., radio, and internet, and we have a problem Houston.
The Orthodox Solution:
As anything Orthodox, keep it old. 14-15 was a great age to get married (and no it was not always a 50 year old man marrying a 14 year old girl - stop watching Fiddler on the Roof). Nothing morally wrong with it. The God & the church endorsed it completely. The young adults "grew together" rather than becoming set in their ways then getting married later on for complications and over a 50% divorce rate (not including shack ups).
The young man enjoyed "the beauty of her youth" as the song of songs states. The young woman had a healthy young male to "get the farm started & home". All sexual tension could be relieved without problem. The young woman was in fantastic child bearing years (16 being the most healthy age medically to have a baby - even modern medicine states this).
Is this practical today - Yes & No.
Yes on a moral & practical ground biologically, no because of suppression.
The World Solution.
4) "party - have fun"
5) Grow older
6) Get money
7) Get set in your ways
Date for 2 years in fornication (possibly move in)
9) Get married
10) Fun for 2 more years, both set in their ways, fight, fight some more, divorce.
But why would we expect more from a moral less society that condemns what God created naturally? The children of the world are evil.