During the long, hot summers in Miami when I was a teenager, we jumped off a bridge.For fun.Which was insane.This bridge was high over a narrow inlet from the ocean ó fast-moving water below, jagged rocks along each side and ó for added insanity ó plenty of boat traffic passing underneath us. And we jumped in and climbed out and jumped again until some adult came to run us off.All these years later I still canít grasp the stupidity of this, the miracle that no one was ever seriously hurt.Does everyone have stories of youthful stupidity bordering on insanity?I knew kids who blew things up, who could have caused serious wrecks throwing grapefruits at passing cars in the dark, who pointed BB guns at each otherís faces, all in the name of fun.And I knew kids who raced revved-up cars on public streets who could have killed someone.What happened on Bayshore Boulevard three weeks ago today is still unfathomable: A woman named Jessica Raubenolt was pushing her little girl Lillia in her stroller when they were hit by a speeding car.What police say the 18-year-old driver, Cameron Herrin, was doing was beyond stupid, beyond dangerous: racing a 17-year-old friend down a road where people run and bike and walk their dogs. And assume they will be able to cross the street without dying.Herrin and the other driver, John Barrineau, now face the appropriate charges of vehicular homicide, street racing and reckless driving. Herrinís brother and passenger Tristan is charged with misdemeanor street racing.It will not help in the court of public opinion that these are children of privilege, or that the car that killed a mom and a little girl not quite 2 was a brand-new Mustang built for speed and a gift from his parents.Or that at some point the car is believed to have hit 102 mph.To be clear here: Youthful stupidity is no defense. A father walked out on Bayshore that day looking for his wife and daughter who had gone for a walk along the water and found police, paramedics and a mangled stroller. I mean, I donít know what defense there could be.And none of the ó boys? young men? ó had been in serious trouble before. So much is wasted here.But when you are young, you think you are invincible.Nothing truly bad can happen to you, because, hey, nothing has so far, right? You are a teenager, your brain not fully formed. Things adults say in warning wash over you like air.Because how is it possible that one bad choice, one truly stupid decision, could change everything for the rest of your life, when you havenít even figured out what the rest of your life is going to be?If anything useful can come from this horrific tragedy, maybe itís one kid who thinks of what happened here a split second before he does something stupid because everyone else is doing it, because it seems like crazy fun at the moment, until everything, their entire world, changes.Maybe itís one kid who thinks before he does what he can never take back.