Which excerpt from "Soldier's Home" is the best example of irony?

The excerpt from "Soldier's Home" that would be the best example of irony is: Nothing was changed in the town except that the young girls had grown up. They all wore sweaters and shirt waists with round Dutch collars. It was a pattern.

The excerpt conveys that even though the condition int he town has changed and the girls have become older, they still wear the clothing that they use when they're still little girls.