BUFFALO, NY — The mom of a slain Buffalo mass shooting victim says she’s racked with guilt after asking the young woman to pick up groceries the day she was gunned down.

“I feel like it’s my fault because if she wouldn’t have been going to the store, she would be living,” a guilt-ridden Dezzelynn McDuffie told The Post about 32-year-old Roberta Drury.

McDuffie — who explained she’s not Drury’s biological mother but considers herself her mother figure — said she’ll be forever haunted after seeing Drury’s lifeless body lying in the supermarket parking lot.

“I swear when she left my house … she looked at me and said, ‘Ma, this is going to be a good year for me and you.’ I said, ‘Roberta, it sure is,'” a sobbing McDuffie told The Post on Monday near the scene of the mass shooting.

“Not even five minutes later, she ends up getting killed in the f–king parking lot.”

Drury was among the 10 black people gunned down at the supermarket when 18-year-old Payton Gendron, an accused white supremacist, allegedly opened fire in a hate-filled rampage.

McDuffie said she was going to the store to pick up cigarettes and cheese.

“As soon as [Drury] walked into the parking lot, she was the first one he killed,” a guilt-ridden McDuffie said.

McDuffie, who took Drury into her care seven years ago after a lengthy stint in the foster system, said she rushed to Tops — which is across the street from her home — as soon as she noticed all the police cars.

“I saw her body. I was across the street and … it was right there. It was right there the whole time. That’s what messes me up because when I come out of my house, I still see what was going on,” McDuffie said through tears.

“Every time I come out on my porch, she’s there.”

McDuffie had earlier told the Buffalo News that she had seen the video that the suspect livestreamed of himself gunning down his victims in the parking lot and store.

“When that man killed her, she had smoke coming out of her f–king head,” McDuffie told The Post of the disturbing footage. “She didn’t have a chance for nothing. She didn’t have a chance.”

Standing behind police tape at the scene on Monday, McDuffie said she was “100 percent sure” she saw the alleged gunman at the store doing reconnaissance in the days leading up to the massacre.

“He was getting out of his car. He was taking photos. He parked in the same damn place every day,” McDuffie said. “I’m wondering why people didn’t call the cops and let them know this man is coming every single day. He not purchasing groceries or nothing.”

McDuffie said she would be avoiding all supermarkets in the wake of the shooting, telling The Post: “I’m not going in no Family Dollar. I’m not going into no Tops. I’m not going into Walmart. I’m not going into none of the damn things.”

“It’s sad. You gotta live like that,” she added.