The pairing of a lightweight cardigan over a lightweight crewneck pullover, was known as a "twinset".
More often the two garments would be in a plain matching colour although this woman, to be less formal and more individual, wears a striped pullover and knots her pearls. .
About 18 years old date about 1949 Estimate born 1931 ± 3 years
becoming more formal wear into the early sixties.