You mentioned stepping out or the pool; that's not a classroom full of 16, 13 year old boys (who wake up in a puddle of nut since they're having wet dreams at this age).
No one said she has to hide her shape but she's purposely wearing skin tight clothing. Look at the shoes. Are you telling me that's acceptable?
As a teacher she's walking around, she's constantly bending over, and other movements that's way too arousing for little boys. I find women that's trying to arouse children extremely weird.
Again the shoes she chose to wear tells me everything about her mindset and intentions. If I had boys I wouldn't want them in her class.