Serenity Rangel’s family is grieving the 18-year-old after a single-car crash near North Walton Walker Boulevard and Singleton Road in Dallas on Thursday night. Police said Rangel lost control of her vehicle; surveillance video from a nearby business showed the car overturning after it left the road. The cause of the crash remains under investigation. Rangel’s family and friends said she was on her way to her boyfriend’s home. They have questions about what happened, but no cause beyond the police account has been established. Rangel would have turned 19 next month, her mother, Noemi Rangel-Chacon, said. She graduated from Nimitz High School last year and had begun taking community-college classes. “She was my firstborn, my baby to this day,” Rangel-Chacon said, describing her grief. Candles have been set up in the family’s home in Rangel’s memory. Friend Jayla Carrizales said she learned of Rangel’s death in a message and initially did not understand what had happened. She later called Rangel’s family and was told her friend had died. Rangel-Chacon said she hopes the loss will prompt drivers to reconsider speeding. “There’s no need for any of us to be speeding,” she said, adding that people may believe they are driving safely without knowing what could happen around them. The family is raising money to help cover funeral costs. As they prepare to say goodbye, they are left mourning a young woman who had recently finished high school and begun college classes.