Twelve-year-old Nicole Rossilli never knew her grandfather, Stephen Knapp, who was killed in the 1993 World Trade Center bombing.

But every Feb. 26 — the day of the first terrorist attack on the World Trade Center — the Staten Island girl’s family brings her to the North Tower site where her grandfather, then 47, lost his life.

Knapp was one of six people killed after radical terrorists loaded 1,200 pounds of explosives inside a van, then parked it in the World Trade Center’s underground parking garage, where it exploded. At least 1,000 people were injured in the attack, which occurred at 12:18 p.m.

On Sunday, the families of those who died in the attack laid roses on their inscribed names at the reflecting pool where the North Tower once stood.

This year’s ceremony came just days after the death of Egyptian cleric Omar Abdel-Rahman, believed to be the mastermind behind the bombing. Abdel-Rahman, also known as the “Blind Sheik,” died of natural causes Feb. 18 in a North Carolina federal prison at 78.

“It’s not fair that he got to live his life, but not my father,” said Knapp’s daughter, Denise Rossilli, 40. “He did not deserve to live out his life.”

Knapp was chief maintenance supervisor with the Port Authority of New York and New Jersey, and Rossilli has not missed an anniversary that marks her father’s death.

After laying white, pink and yellow roses on her grandfather’s name at the National September 11 Memorial & Museum, Nicole said: “I’ve learned that this should have never happened.” She vowed to return each year “for the rest of my life to remember my grandpa.”

Charles Maikish, former director of the Port Authority’s World Trade Department and former executive in charge of recovery after the 1993 bombing, said that Rahman’s death “was basically a milestone in this country’s fight against terrorism.”

“It should be about peace and that there was peace in his death and that it brings peace to all of us,” he said at the end of Sunday’s ceremony.

Former Port Authority employee Marileen Brown of Fresh Meadows survived both the 1993 World Trade Center bombing and the Sept. 11, 2001 attack that took down the towers.

After the first bombing, which occurred on a Friday, she remembered returning to work the following Monday.

“We still had to attend to business,” she said.

On the day of the 2001 attacks, Brown felt the North Tower shake when she stood on the mezzanine floor after buying her lunch.

“I was waiting for the elevator when I felt it and knew right away, ‘here we go again,’” she said.

It took almost 10 years for her to return to the site. Sunday was her first time attending the ceremony for the 1993 attack.

“I suffer a lot of survivor’s guilt,” she said. “I just wish I was able to at least save one life.”