A breakout star in “Roma,” first-time actress Yalitza Aparicio went from small-town schoolteacher-in-training to snagging a lead role in director Alfonso Cuarón’s autobiographical movie about his formative years in Mexico. Aparicio plays Cleo, based on the director’s childhood nanny. “It’s kind of incredible that I’ve had this experience,” she says, “because not everybody starts this way.”

How did Alfonso find you?

He deployed a bunch of teams around Mexico to indigenous communities for casting calls. I happened to be lucky enough that one of those teams came to my hometown of Tlaxiaco, a very small town in Oaxaca. My sister found out about the casting call, and she dragged me along.

We’re told you were teaching school before “Roma.” Were you teaching right up to the point that you auditioned?

I really love teaching; I was actually studying to be a preschool teacher. I had only finished my schooling a month before I was cast for the film, so I have not yet had my own classroom. I’ve now realized I like both things. I’ve realized that acting in films is another way of teaching — just at a mass scale to reach a larger audience.

What was the first thing you did when you found out you’d been cast?

I went back home and told my family, and we were all kind of in this state of shock. We couldn’t really believe it. My brothers asked me, “How are you going to do this?” Because I’m very camera-shy and also the quietest member of the family. And so they were like, “What are you going to do when the camera starts rolling? Are you going hide?”

How did you overcome that fear?

At first it was kind of scary and overwhelming, but I had to pretend like the cameras weren’t there. And as time went on, I got very good at that, at imagining that I was on set by myself, just performing day-to-day tasks.

Things You Didn’t Know About Yalitza Aparicio

Age: 24 Birthplace: Tlaxiaco, Oaxaca, Mexico Favorite Movie: “The Lovely Bones” Author Who’s on Her Nightstand: Lydia Cacho Favorite Food: Mole