Trying to find a certain drama

Hi all,

Long time viewer of Tvtropes, but a first time poster. I'm hoping someone can help me here. I've been trying to locate the name of a film I saw years ago.

It is set during Summer (I think). The main character is a girl who lives with her mother. There is a stray cat that they feed. The young girl gets a temp job at a cafe or restaurant at a beach with someone that she knows (possibly an older sister). There is a scene during the movie where the young girl is hanging with the older one and the older one's boyfriend on the beach at night. There was also a scene in it where the young girl was throwing something (possibly rocks) with some others and it broke a window. A boy took the blame for the girl and was beaten for it. The girl ends up teaching the boy how to swim.

• spoilers* One day the boy swims without her and he ends up drowning.

I know it's not much to go off, but does anyone have any ideas?

I got nothing

And this isn't the place to ask about what movie this is.

The place to ask is You Know That Show.