This doesn't look good.
The immediate effects:
I found an estimate that at any given time, there are roughly 19 million drivers on the road at any given time. Given that all (or at least the overwhelming majority) of them will be 15 or over, That's 19 million cars in the US alone suddenly veering out of control at houses, buildings, power poles, pedestrians, each other, you name it. About half of that many passengers will be riding along, so even if they're not raptured due to age, things don't look pretty for their future.
Many kids/teenagers will die when a car comes crashing through the wall, when another car collides with theirs, or when they get outright run over on the sidewalk. Power poles go down.
Some kids/teenagers will die when the surgeons operating on them do, others will die when that gorilla whose enclosure they climbed into at the zoo has nobody to shoot it. People carrying heavy things will drop them, some of these might roll and cause injury, death or infrastructure damage.
Now how does our infrastructure look?
Actually worse than the sudden deaths suffered by out-of-control cars, highways become impassible from the sheer volume of wreckage strewn about. Bonus points if the event struck at rush hour. Neighborhoods are without power, and probably some parts of urban areas too. In the most extreme cases, perhaps a delicate operation was underway at a power plant or two and now power has been lost totally for a large population.
Most of the population was without income to begin with, and the rest are now both very short on customers and managers. As funds run out, the automated systems that manage electrical access turn off the utility in large quantities accross the board... supposing anyone lives that long.
The guy who reads emails and fulfills orders for grocery store stocking is gone now, so distribution of food is kaput. Even those distributors who automate this have no truck drivers to fill the orders. Even if there were, the roads are completely impassible from wrecked cars. Nobody will make the order to producers, but then again there are very few producers left anyway.
Running water is probably ok though. Most of those companies still rely on workers manually shutting off the utility. So not many will be dying of thirst until water towers run dry. I guess that's a plus.
So who fixes all this?
Kids and teenagers will probably prove much more resourceful than adults would expect, but even so many of the positions that are most crucial in our infrastructure require specialized education or training that most of the survivors would not have. Perhaps a few uncannily-minded individuals would fill some gaps but overall the skills simply won't exist to remedy most of these problems.
So where does that leave us?
We're back to hunting and gathering within weeks or even days. Many of our youth will no doubt be fine with hunting until the ammunition runs out. With enough ingenuity, some kids and teenagers will be able to survive anyway. In an ironic twist of predator-prey curves, despite the large amount of prey, there are too few predators among the survivors. Those less capable will flock to those more capable. Limited resources (the prey) cause contention and conflict. The population isn't sustainable and drops rapidly.
As more and more fall back on ancient methods of survival or die outright, even those equipped with the skills to uphold infrastructure are left with nobody to uphold it for.
So we're all dead?
Some survivors might squeak by when all is said and done by making an effort to isolate themselves immediately and having the skills to survive. Perhaps they can find enough resources to provide for themselves and a friend or two. So I guess we're not all dead...
