[Not only is Ai thinking about herself but also what Kija said to her earlier. He wants to be out in the sun. There are better things they could be doing besides sitting around reading books. While that might be nice every now and then, they should also be enjoying this nice day.
Ai looks at him as he starts in on the title but doesn't need to glare even a little before he's correcting himself.
With books in hand, she leads the way to library to return them so they can continue on unhindered by the load. It certainly will keep her mind off her parents and there are plenty of ways for this to work out. She's already thinking about the many ways (a few which may fluster Kija).]
As have I and I wanted to do it. When you live as long as we do, Kija, you have time to become interested in many things.