Even as Aparicio is celebrated, she has become a target of racist attacks online. Aparicio said that while it initially upset her, she is now focused on the scores who have called her a role model and sent fan art. “I’m not the face of Mexico,” she added, since the country has many faces.

Image This cover made history for Vogue México. Credit... Vogue

The editor in chief of Vogue México and Vogue Latinoamérica, Karla Martinez de Salas, said she witnessed the racist and classist reactions to photos of Aparicio in Vanity Fair, and worried that the Vogue images would meet a similar response. Rather, they were celebrated with the largest response the magazine has ever received on social media.

In the park, Aparicio sat facing the sun. Her best friend in real life and on film, Nancy García García (who plays Adela, the cook), has told her she looks tired these days. She feels tired. In August, Aparicio flew to Venice for the premiere of “Roma,” where she watched the movie for the first time. She tried to contain her emotions, but 30 minutes in, she began crying, and continued until the closing credits. It has been a whirlwind ever since, with trips to London, San Francisco, New York, Toronto, Los Angeles and more.

The journey actually started two years earlier. The director of a Tlaxiaco cultural center had invited Aparicio’s older sister, Edith, to a mysterious casting call that would turn out to be for Cuarón’s big-screen portrait of Cleo and Mexico City in the 1970s. Casting the lead was a monthslong process that involved tapes of more than 3,000 women, none of whom Cuarón found quite right. At the audition, Edith Aparicio, who was pregnant, hesitated and urged Yalitza to try out instead so she could recount the details.

Cuarón met her at a callback. “I was starting to get a bit nervous until suddenly Yalitza walks into the office, and it was that presence — kind of shy but very open,” Cuarón recalled by phone. He’d been looking to match the sensibility of Libo, an empathic way of relating to others.