As a single skater, Kielmann began her breakthrough in the 1987–88 season. After winning the national silver medal, she was assigned to her first major international event, the 1988 European Championships, and came in ninth. Represented West Germany at the 1988 Winter Olympics in Calgary, Kielmann placed 12th in the compulsory figures, 11th in the short program, 10th in the free skate, and 10th overall. She finished as the second-ranked West German, behind Claudia Leistner, and fourth-ranked of all the Germans in ladies' singles. She placed 12th in her final event of the season, the 1988 World Championships in Budapest.