Did you not grow up around other children? Someone died in my neighborhood where I grew up because they decided to run after a ball and got hit by a car.
Children have near-zero responsibility (babies probably have zero, period), so even if the decision making abilities of children was the same as college students (it's not), then the sheer difference in responsibility levels alone would produce different ratios.
I *think* what you're trying to say is that college students tend to have that sense of invincibility that comes with youth, which in turn leads them to make poorer decisions than they would have otherwise made without that sense of invincibility.