Wild Geese(2018)

When Amy catches her husband in the act, she falls down the stairs, bangs her head, and wakes up with amnesia - believing she is 16 and that the year is 1999. Aside from the wrinkles on her face, Amy is a teeenager again - outspoken, hormonal, obsessed with emo poetry and, crucially, fixated with tracking down her high school best friend Polly.