The book that I am trying to find was purchased via scholastic books (or similar) in the 1978-1979

school year. Probably Spring ’79.  It was young adult fiction and either the back cover or the description said “Rites of Passage” (then something about learning to drive,graduating,etc.)

The book began with the heroine and her family cleaning out a beloved family cabin or cottage. Her grandmother had just died and she was having trouble dealing with it. A female cousin shows up and they don’t really like each other. Later in the book they become close.The cousin has become cool by sewing shift dresses for classmates. The dresses are unique because she added a pop art twist to

each dress. The cousin would appliqué a hamburger up by a shoulder or a little snake at the waist.

The heroine is dating / deciding between two boys. One is a freshman at MIT / ridiculously smart. One of them gives her a rock from Cuttyhunk Island. I had never heard of this Island and was taken with the idea that it could produce perfectly round rocks because of tides and gravity,etc. For a work of fiction,it explained it pretty well.

The heroine keeps the rock as a talisman ( learned that word from the book ) and at the end of the book throws it into the sea because she doesn’t need it any longer.

That is all that I remember. Thank you for your help.