Across the board age discrimination doesn't really work.
I have dealt with 20 year-olds who really should not be left out on their own overnight. I have negotiated traffic stops with physically healthy 43 year-olds who should not be allowed to drive on their own, and never should be allowed access to anything more dangerous than a hacksaw or a pea-shooter. I have met 12 year-olds that I think should be granted status as adults for the felonies that I have seen them brazenly commit. I have met 11 year-olds that I would have no problem with, if they went on a trip overnight in rough territory, or kept a house by themselves, armed at all times.
Some human beings are simply more capable than others. Some are capable to a completely satisfactory adult level, long before their birthdate has reached magic numbers of, say "18" or "21" or the like.
Somewhere out in the Indian Ocean is a 16 year old young lady named Abby Sunderland, who had displayed enough drive and ability that she was given a shot to pilot a sailboat on a voyage around the world. It now looks possible that she's not going to live through that voyage, due to inclement weather. ** Such single-person sailing expeditions can be dangerous. It happens.
But teenagers die on their way to school in their cars, and they perish in odd accidents that you wouldn't have expected. And they die at home. None of us gets out of this life alive.
But, for a time, she was captain of her own vessel, and completely in charge of her own destiny. Not a lot of 16 year-olds can say that. Probably most aren't ready to do so. But she and some other people evidently thought that she was ready, and she tried to live just a little bit more than most of us do.
I can't make myself judge her parents for that. They know if she was ready.*
*Insofar as the costs of the rescue efforts go, I firmly believe that is between her family and the Australian rescue groups. That absolutely must have been considered before such an endeavor was attempted.
**EDIT: Turns out that she's fine.