This is why it is "better" for a person who is 50 to die while skydiving, rather than a person who is 16. A teenager is young, and full of hope and potential and blah blah blah. But that is also a huge investment on which no one will ever see a return. The fact that old people die with vast stores of accumulated experience and knowledge is just a basic fact of death, and will happen to anyone at any age.
It takes a tremendous amount of resources to raise a child, most of which can be quantified as a dollar value. For instance, it will cost your parents $1 milllion to raise you to the age of 18; this is both in actual money spent because of you, and foregone opportunity costs from work. Then there is the cost in tax dollars from public schooling, and other such things.
When you add up all the numbers, the average person has not made a positive contribution to society (as far as dollars are concerned) until their late 30s. If you cannot see the value in "investing in our children's future," think of it as an investment in society itself that will pay off decades down the road.
And as a slightly political footnote, this is one of the reasons America was so prosperous during the middle part of the 20th century. The GI bill financed a great many college educations, and then there was a lot of investment in science education in order to "fight" the Cold War, and produce world class scientists. Much of that has since been cut, mostly by the Reagan administration, and today the US is no longer #1 at anything we would like to be proud of.