I think I understand. It's not something in the story itself, it's what you would want for Candy. (We're talking about her as if she's a real person rather than a plot device and a drawn image, but that's part of reading fiction). Candy doesn't show any sign at all of having thought about college or a career. Of course, this is just a quick little story in a comic book, not a mainstream novel and we don't really get to know the characters that well.
And in real life Bob might not just shrug off that he'd been seeing a fifteen year old who lied about her age. It's kind of odd that no one else mentions this to him during the weeks they're dating. ("Say, you know she's jailbait, right Bob?") The way he reacts makes me suspect he wasn't deceived at all and just went along with it.