One hundred days from yesterday

Sixteen years old. That's how old Ava was when her mother had committed suicide. Her twelve year old sister , Elizabeth, was sent off to her aunts house while Ava had to stay back and sort things out. Her mother had left a letter, a letter Ava told no one about, but when the police find it, Ava is seemingly linked to the suicide. mentions of self-harm, bullying, (succeeded/failed) attempts of suicide, underaged drinking, etc.