Cintrón first fought in public in the Plaza de Acho, in Lima, in January 1936. On July 31, 1938 she made her debut as a "novillera", also in Lima. This event established her as a professional rejoneadora, a rare (but not unprecedented) honor for a woman. After a trip to Portugal, she was invited to perform in Mexico. She made her Mexico City debut at the Plaza del Toreo on August 20, 1938. She failed to kill her bull, but nevertheless was a great hit with the crowd and the taurine critics. She was reported to have "caused pandemonium in the stands".