Not Quite Dead Yet by Holly Jackson

The #1 bestselling author of A Good Girl’s Guide to Murder—now a hit Netflix series—returns with her first novel for adults: a twisty thriller about a young woman trying to solve her own murder.

In seven days Jet Mason will be dead.

Jet is the daughter of one of the wealthiest families in Woodstock, Vermont. Twenty-seven years old, she’s still waiting for her life to begin. I’ll do it later, she always says. She has time.
Until Halloween night, when Jet is violently attacked by an unseen intruder.
She suffers a catastrophic head injury. The doctor is certain that within a week, the injury will trigger a deadly aneurysm.
Jet has never thought of herself as having enemies. But now she looks at everyone in a new light: her family, her former best friend turned sister-in-law, her ex-boyfriend.
She has at most seven days, and as her condition deteriorates she has only her childhood friend Billy for help. But nevertheless, she’s absolutely determined to finally finish something:
Jet is going to solve her own murder.