She’s guilty as are all adults who have sex with minors. Appearance has nothing to do with it.
Many (most?) teachers are liberal. Most liberals are immoral. When a person is sexually immoral in their private life, that attitude may very well extend to their professional life given the opportunity.
Teachers are in an authority position over students. In my opinion, it doesn’t even matter if a student is legal age. People, like President Clinton, who use positions of authority to have sex with subordinates are at least very unprofessional.
Minors, by definition, are incapable of giving informed consent to sex with an adult—the perceived hotness of said adult being completely irrelevant.
Lighten up, dude (or dudette)
It's an ongoing joke around here to judge the guilt or innocence of females based on their appearance. It's meant to be lighthearted, not a sign of moral deficiency.