Learning is never a waste of time.
In hind sight we can see how immature it is for a 15 year old to believe he/she has found their "soul-mate"!
Even those who go off to college after high school graduation are often naïve enough to believe they will maintain a long distance relationship for the next 4-6 years and eventually marry.
Most of those relationships end after one or two semesters when one or both of them decide they want to participate in social activities with those on their college campus. They're still evolving and figuring things out.
Countless times parents have attempted to steer their teens away from seriously getting involved in relationships. Generally it fails because most teens tend to believe they are smarter than their parents. They feel their parents don't know what "true love" is.
Another factor during the teenage years is raging hormones and sexual awareness. A lot of girls in particular seek to have a bond with the first guy they have sex. In the U.S. the average person loses their virginity at age 17. Most girls don't want their first time to be a "one night stand". It's usually within a serious relationship.
Teenage love is period of learning about yourself as well as what you want and need from your idea mate. Truth be told most of us (fail our way) to success when it comes to love and relationships.
To my knowledge there is no evidence that suggests if one avoids serious relationships during their teens they are guaranteed to find their ideal mate their first time out the gate.
There is nothing wrong with being focused on one's education and career goals while primarily dating around for fun. However there is no reason to "tell someone off" because they want something different from yourself.
Whatever you don't want another guy may want. It's not about "right" or "wrong" but rather "agree" or "disagree". The goal is to find someone who naturally agrees with us and shares our same values.
Falling "in love" the first time is easy for most people. The real challenge is allowing themselves to fall "in love" a second or third time after they've been betrayed or had their heart broken. Some folks never completely recover after the first heartache. They never fully allow themselves to be "all in" with another person again. It takes courage to put yourself in a vulnerable place.
Teenage love is often fantasy love. There are no jobs to work, bills to pay, or emotional baggage.