Twinsets were big in the 50s and early to mid 60s. My mom had several. A twinset is a short-sleeved sweater with a matching long-sleeved cardigan. The advantage was you wore both pieces in the fall and winter, while you wore the short-sleeved piece in the spring and summer.
Watch "Tammy and the Bachelor" or "Blackboard Jungle" to get an idea of what teens actually wore during that time, and any episode of "I Love Lucy" to see how women were dressing during the time. Lucille Ball always had great clothes for that show.