Y/A, girl goes to school with aliens who have powers and live on a beach, big battel at the end of the book

[Sarah]

I read this book in the last 10 years and when I read it, it was fairly new. A girl goes to a school where aliens or creatures recently started going. These creatures live on the beach and have special powers. She becomes friends and falls in love with one of the creatures. The creatures look like humans I'm pretty sure. In the end, she realizes that her mom isn't dead but is one of these creatures and a big battle takes place between the creatures and another group of people. I think the first scene of the book is her in a bathtub of some sorts.

[Tris]

I think this is “Undertow” by Michael Buckley!

[Paige]

Undertow
For Tris' suggestion.