It is quite possible for a teen to fall in love, but, as you said, for a time. Love should be taken seriously. the result should be that of a lifelong commitment. It is not bad that the teen falls in love so much as that both/either blow a great deal of time, energy and money in the other and then break up. Bam, shattered feelings, devastation whatever else. Murder, even, as exemplified by the girl whom had her boyfriend kill another out of jealousy.
A teen should not seriously date until s/he is ready to actually commit to the other person, marry and maybe raise a family. This is no small commitment. You direction and attention changes from yourself to your spouse, and then to a family.
A teenager is not often ready to give up that freedom, which is often a case in abortions. "Oh, I didn't know!" Well learn.