lesbianism is no excuse!
Two criticisms:
1) How could this girl be seventeen!? She looks like a very polished 24-29 year old! Not only that, but her actions are way too mature... particularly in the scene where she hugs the teacher at the beach house.
2) I hate movies where people don't seem to have control over their actions! A 32 year old teacher having sex with a 17 year old student WTF!? If that were to happen in a movie about a male teacher and his female student (or even a male teacher and his male student) people would be outraged. I am still outraged. I think that the teacher should know better, as should any responsible adult who is considering taking advantage of a child (or in this case, a 17 year old who is sexually precocious).
I want to have sex with people all the time... I just have enough self control and common sense not to do it!
In my opinion, this movie would have been 100 times better had the relationship been struck between a young teacher's aide, or maybe even a candidate for the monastic life, and the teacher. The student-teacher relationship just makes it seem so trivial and frivolous to me.