Like, "you can't drive until you're X years old, because, even though it might be fine, you'd likely be too big of a risk for yourself and others" makes total sense.
And so too does "you can't drive after you're X years old, because, even though it might be fine, you'd likely be too big of a risk for yourself and others"!
But I've never heard of a country that does it like that. Why not?
Did you know that you have to be 35 or older to run for POTUS? But there's no upper age limit.