It was a 6-foot-high wooden wall -- a head taller than her -- part of an obstacle course at the El Camino College athletic fields. Over the next six weeks, Wolf threw herself at the wall over and over again, for several hours at a time. Her arms and legs became black and blue with bruises. But she was ecstatic the day she finally clambered over it.
The Army sergeant approached everything else in life with the same dedication and vigor, whether it was the Police Explorers, the military or motherhood, her friends and family said.
In October, five months into her first tour in Afghanistan, a captain in her unit asked for volunteers for a supply mission. Wolf raised her hand even though she was still recovering from an injured foot. She refused to use crutches or take pain medication and wanted to do everything like her fellow soldiers, her family said.
"Typical Duvi," said Susie Martin, a police service officer who supervised Wolf in the Explorer program, recounting the story. "Everything about her was enthusiastic. . . . If it was something fun, she was the first one to volunteer. If it was something nobody wanted to do, she was still the first one to volunteer."
The supply mission would be her last. Wolf was killed Oct. 25 when her vehicle was attacked with a rocket-propelled grenade in eastern Afghanistan's Kunar province, on the Pakistani border. She was 24.
She was an automated logistical specialist assigned to the 704th Brigade Support Battalion, 4th Brigade Combat Team, 4th Infantry Division at Ft. Carson, Colo.
Wolf, whose maiden name was Preciado, grew up in Hawthorne as the youngest of four sisters in an immigrant family from Guadalajara, Mexico.
From a young age, she was responsible and focused, a tomboy who always kept her hair pulled back in a tight ponytail and wanted to run around outside when her cousins wanted to play with dolls or experiment with makeup.
Her father, who worked as a gardener, taught all his daughters to play the violin. But Wolf played exceptionally, her family recalled. Her father beamed as he distributed CDs of her mariachi music performances to friends and family.
Wolf's dreams of becoming a police officer began with the television show "Cops." The sisters crowded around the TV and sang along to the theme song, recalled Wolf's sister, Ana Ross. They used their father's video camera to make their own version playing cops and robbers, and admired the officers on the show for the work they were doing to protect the community, Ross said.
Wolf joined the Junior ROTC program at Leuzinger High School and the Hawthorne Police Explorers. She recruited a number of her friends to the Explorers, soon tripling the size of the program that began with about five teenagers when she first joined, Martin said. Wolf rapidly rose through the ranks, becoming a lieutenant in the program.
After she graduated from the Explorers, she joined the Army because she was still too young to become a police officer, said Ross, who followed in her steps three months later. "She always led the way," said Ross, who is three years older but looked up to her younger sister as a role model. "She was much braver than I was."
Wolf's family worried about her safety. Martin, who said the girls became like daughters to her over the years, said they didn't talk to her about the military because they knew it upset her. But, in the end, Martin and her family respected and supported her decision. "I know she did it for her country, and she did it proudly, and did it unselfishly," said her cousin Eufemia Aguilar.
In the Army, Wolf joined the airborne school to become a paratrooper but had to drop out when she developed stress fractures in her hips and legs during the rigorous training.
She soon found something else: She fell in love with a fellow soldier she met at Ft. Bragg, N.C.
Martin recalled how happy she appeared when she came to visit with her husband, Army Sgt. Josh Wolf. "She was like a little schoolgirl with stars in her eyes," Martin said.
The young couple began building the foundations of a family life. Wolf gave birth to two daughters. The couple bought a home and moved to Colorado. Then, this summer, both of them were deployed to Afghanistan.
Wolf had a hard time being away from her young daughters, Valeri and Isabel, who stayed with their grandparents in South Dakota. Wolf talked about missing Valeri's first birthday and not being able to pick out a Halloween costume with Isabel, who was 3.
But that didn't mean she was any less enthusiastic about her career in the military.
Wolf told her family that her time in Afghanistan was fulfilling, and she reenlisted for another three years just a week before she was killed, Ross said. Wolf was due to come home to her daughters for a two-week leave in mid-November. "We pray for her every day," said Ross, who left the military after four years of service and now lives in Georgia with her parents. "She was my sister, my best friend."