"What is that?" she asked in Spanish. "Is that where you put the gas?"
Her eldest son, 15-year-old Ernesto, laughed before explaining that the Nissan Leaf requires no gasoline. He encouraged her to sit in the driver's seat.
The Peña family was one of many attending the first day of the annual state fair in Dallas.
Fair officials no longer release attendance counts but last year pegged the number at about 3 million. A spokesman said nearly 85 percent of those attendees take time to see the hundreds of cars and trucks showcased at the fair each year.
"It's like I'm in a candy store," said Ernesto, a car enthusiast. "I turn 16 next year. It's my big chance to show my mom and dad the best gift suggestion."