That's a good average age for the worst group IMO. We have a large university in our town and the young women attending there are downright scary (as drivers) on city streets. I do have the advantage of driviing a Suburban (I'll walk away unhurt) but these lovely young drivers still pull driving stunts that cause me to cringe - question their sanity.
Actually, they think nothing will happen to them (many younger drivers appear to believe this) so they take chances - depend on other drivers giving them the room and time to "do their thing."
One other group actually drives worse, but it's clearly not PC to point them out (black women.)