SHERRY: Except that our colors were white and bright red. I looked hideous.
CHRISTOPHER: Oh, she’s being self-deprecating. You looked cute in that outfit.
SHERRY: No no, I looked like a peppermint stick. I swear, that’s where my addiction to clothes comes from. Trying to make up for all the years of having to wear the same thing every day.
A peppermint stick is a long stick of hard candy with peppermint flavouring, traditionally coloured with red and white stripes. They were developed in the US, and are often marketed as an “old fashioned” or traditional candy. They have been sold since at least 1837, when they were shown at an exhibition in Massachusetts, and were popular by the 1860s. By the early 1900s, they were already viewed nostalgically.
I don’t know of any private school in the US which has a bright red and white uniform. Note Sherry’s implication that she was very slim as a schoolgirl, when she compares herself to a skinny peppermint stick.