I was probably 16/17 when I had my first "serious" girlfriend.
Like most teens I believed I was "grown" or mature and was ready to take on the world. I thought the adults didn't know what they were talking about and had never "felt" the way (we) felt and so forth. Like a lot of "first love" relationships we thought it was also our "last love" and we'd go off to college, get married, have children, and live happily ever after...some day.
We were fools!
We were too immature to realize how "unrealistic" we were!
First and foremost "teen love" is completely different from (adult) love. A teenager has no obligations, no overbearing boss, a demanding job, mortgage/rent, car note, and utilities to pay. The most stress they have to deal with is doing homework and obeying their parents. The rest of the time they can "fantasize" about their future together.
During our teen years our hormones are also raging coupled with our lack of relationship experience we quickly make assumptions and (completely immerse ourselves into one another) oftentimes at the expense of losing our own identity. Many teen couples (act) as if they're already Mr. & Mrs.!
The truth is most of us (fail our way to success) when it comes to relationships. Our "shopping list" of traits we want in a mate will change dramatically over the years! This makes it highly unlikely one is going to meet their "soul mate" at age 15,16, 18, or even at 21. Truth be told we have not figured out (who we are) let alone what we need.
I think it's great to have that "first love" and experience being "in love" while living in a (safe cocoon) where one's parents are taking care of all their material needs. The only way an adult couple can experience that kind of freedom to love like that is if they win the lottery and have none of the stresses that we typically have. This explains why people often look back on their "first love" with so much fondness. Everything was (new) and life was "carefree".
I do believe age 16/17 is ideal to start forming relationships, going out on dates to movies, football/basketball games, dances, proms, and other school functions. I just wish we were mature enough to know that we're simply gathering dating/relationship experience at that stage in life.
Having unrealistic expectations of ourselves and others during our teen years leads to the biggest heartbreak of all. However with pain comes growth and wisdom.