What's the title of this coming of age movie?

I remember watching this 80s movie a few yrs ago, but can't remember the title. I googled as much as I could to no avail. I entered a quote from the movie, but bupkis. It isn't much, but I hope someone remembers. It's an 80s movie I believe.

It's about a young girl. The only scene I remember is her and her family in the car, while a young boy (don't think he's related), also in the car begins to taunt her, telling her she's "sexually repressed". He thereafter yells; "you're repressed!" a few more times. Fed up with the taunting, the young lady angrily takes her top off. Obviously trying to prove him wrong. It actually was a good movie, but forgive the fact that this is the only scene I remember. I'm a guy :).

The Sure Thing (1985). The scene in question is alluded to as the "tension and bickering" in the Wikipedia entry quoted below (https://en.wikipedia.org/wiki/The_Sure_Thing)

Walter finds a ride from a ride share board to make the trip. He meets Gary Cooper (Tim Robbins) and Mary Ann Webster (Lisa Jane Persky), the couple providing the ride: they are extroverted and upbeat to a fault. Things go from bad to worse when he realizes he will be sitting next to Alison as she heads to UCLA to visit her boyfriend Jason (Boyd Gaines). The tension and bickering between Walter and Alison becomes too much for Cooper (...)

Here's the scene in question, and here's the trailer: