Knowledge can in some instance just be a bunch of things you learned in a book, while wisdom can’t be built through reading. It’s life experiences that shape you.
In my experience, younger sisters like to get on your nerves.
But that’s knowledge, not intelligence. I’d say the two are different. You can’t learn to be intelligent.
Okay, now combine the horror of a younger sister with a 14-year-old girl. Now you get Lea.