Continuity mistake: In the scene on the sidewalk where Bev is pretending Faye is her mom (and she's practicing to tell her mom that she's pregnant) the same people walk by several times. I don't think there was a single shot-reverse-shot sequence that had the right people walking by at the right time. You saw the same couple, for example, walk by at least four different times.
Factual error: The movie takes place in Connecticut from 1961-1986. All the cars in the movie have license plates on their front bumpers, but Connecticut didn't require front plates until just a few years ago (late 90s-early 00s).
Continuity mistake: After Beverly has her baby, in the hospital her father is going on about how she's fifteen years old and can't handle the responsibility. The movie, movie summary, and special features on the DVD all mention that Beverly was 16 years old when she had her baby. Wouldn't her own father know how old Beverly was?