Shelley was born on July 6, 1947 in White Plains, New York, but grew up in affluent Greenwich, Connecticut, her father being a Wall Street financial analyst. She was a tomboy and it was apparent that she had inherited the willowy, cosmopolitan beauty of her mother, a former airline stewardess and Conover Model. She is the oldest of six children, and she says, "It was a real nice upbringing, I wasn't spoiled." She went to nearby Greenwich Academy and graduated in 1965; but during her junior year, she was discovered by millionaire Huntington Hartford at a debutante ball and he urged her to try modeling. She became a one of the most sought-after teen models and modeled during her summer breaks. She said, "Modeling was a great summer job. It beat waitressing." Later, she went on to Smith College and graduated in 1970 with a degree in History.