People: Mar. 31, 1986

For the past month, after classes at Princeton, Brooke Shields has been slipping into New York City to rehearse, and last week she made her off- Broadway debut in Marguerite Duras' 1977 play The Eden Cinema. The setting is French Indochina during the 1930s, and Shields, 20, portrays Suzanne, a fetching 16-year-old who is courted by a rich plantation owner. Director Francoise Kourilsky approached her for the part last year. Shields, who is majoring in French literature and had studied Duras' work at school, readily accepted her first professional nonmovie role. "She is a very strong actress," says Kourilsky of her star, "and takes direction very well." The reviewers' grades are due this week.