MARGE WOLF is 96 years old and just five feet tall, but she has the heart of a lion!

When a would-be robber wearing a mask flashed a knife and demanded that she open the cash register at the store where she worked, the gutsy great – grandma refused – and told the creep to scram!

“He ordered me time after time to open the regis­ter,” said Marge, who’s operated her family’s mom-and-pop shop, Wolf ’s Grocery, in Marshfield, Wis., for 54 years.

“He even laid his pocket knife on my counter, but I refused point-blank. I’m not gonna be frightened by anybody!”

Marge, who has three children, six grandchildren and 12 great-grandkids, is “an institution in this town,” said Marshfield Police Dept. Lt. Darren Larson.

“We don’t rec­ommend that people put up the level of resistance that Marge did. We’re just ecstatic that she’s OK.”

The feisty senior citizen’s stand-your-ground moment unfolded on July 15.

“The guy came in wearing a silver homemade mask and a black scarf around his head,” Marge re­called.

“He said, ‘Open up your cash reg­ister.’ I said, ‘I’m not opening that cash register for nobody, not you either. I’ll give you all the Tootsie Rolls you want.’

“He said, ‘I don’t want no Tootsie Rolls. I want money. Now open up that register.’ ”

That’s when the thug laid his pock­et knife on the counter. Marge said she looked him in the eye and told him again that she wasn’t opening the register.

“He looked around like he didn’t know what to do,” she said.

“Then he spotted my security camera. I pointed to my medical alert device dangling from my neck and said, ‘I’ll press this button and I’ll have someone here in two seconds. Now get the hell out of my store!’ ”

Sure enough, the creep high-tailed it out the door.

At first, Marge didn’t plan to even call police. But she was worried that the would-be robber, who fled empty-handed, might try to hold up someone else.

Cops have arrested Cordell Elling­son, 17, of Arpin, Wis., on charges of intentionally contributing to the delinquency of a minor after he was accused of encouraging a 13-year Marshfield boy to rob the store.

The two wanted money to go “swimming and drive around,” po­lice say. If convicted, Ellingson faces up to six years behind bars and a $10,000 fine.

The 13-year-old’s case is being han­dled by the juvenile justice system.

“Townspeople are upset that any­one would go into Marge’s store and try to rob her,” said Lt. Larson. “That’s about as low as you can get.

“However, she’s still in great spirits – and behind the counter as usual.”