Looking for a Young Adult book on library shelves in the late ’60’s or early ’70’s.  Julie wants to go steady, but her mother (Cassandra) does not think that she is ready.  Set in a part of the country where there is snow.  Julie is a cheerleader.  Somebody tightens the fit of the uniform sweater and gets in trouble.  Julie wants to wear her mother’s star-shaped brooch.  At the end, Julie gets to go steady and wears the brooch.