To sum it up without spoilers. A female flick version of American Pie.
I've gotten a bit into it. I do gotta say the "family bonding time" in the bathroom was unexpected, and not in a good way. But I'm stipulating this scene is to further convey how young the mom perceives her daughter, and how much control she demands has over her kids. No one has any right to privacy nor bodily autonomy. Of course, moms don't generally bath with their school-aged kids, nor be present when their teen showers.
But if you have any experience being in a mother/daughter relationship, you may relate to the feeling of the need for more privacy and independence, yet parents wanting more clarity and control so they invade your privacy by reading diaries, snooping through everything of yours and ransacking your room, claiming they're "just cleaning". This movie depicts all that in a very literal image.