Jack watched him carefully, ready to pick up any signs of him not being okay. She did no have Chase as a friend right now, that much was certain. She knew taking a break from being Chase's friend was healthy. Whether or not she knew, Jack may end up resenting her, ad that was not what she wanted at all. But it still hurt to not have her friend back. But she and Andrew were cool again, and she wanted to keep it that way.
Therefore she focused her attention on him, trying to gage his reaction to her inquiry, knowing he was still upset by the break up. Jack was probably the most ill-informed on their relationship, but she knew Andrew's relationship with Chase had been destroyed by good intentions, and she knew exactly how much it hurt to try your hardest to choose the option best for everybody, and end up hurting everyone instead.
She smiled at his words, glad to see him giving her a true smile finally, and she grinned wider at the quote which she recognized. "Okay." Then he turned it around on her and asked her if she was okay. In all honesty, she was still upset. How could anyone be "okay" with the summer she had. But that wasn't what mattered. She gave him a half smile and said, "No. But I'm getting better." And that was what mattered.