Consider it a sign of America’s resilience, and New York City’s spirit, on this year’s 9/11 anniversary: The Fire Academy’s class of 2019 will include at least 13 graduates who lost a firefighter father on that day, plus one son of a police officer who perished and two FDNY offspring whose dads died later of 9/11-related illness.

Even as the city mourned back in 2001, it took pride in its fallen heroes: 343 firefighters who perished while trying to extinguish the flames and get stranded office workers out of the burning, collapsing skyscrapers.

They did the amazing things firefighters do: Burdened with pounds of heavy equipment, they sprinted straight toward danger and ran up the stairs of the 100-story buildings as the smoke gathered and walls collapsed around them.

In the years since, dozens of sons and one daughter of the heroes lost that day have joined New York’s Bravest. But this year’s 16 “legacy” members are the most yet.

As Fire Commissioner Daniel Nigro put it, “Bravery runs in these extraordinary families who have sacrificed so much for our city.”

Reason to cheer, among the tears.