ABC News

A gun-carrying grandmother in Milwaukee foiled an attempted robbery when she pulled a firearm on the suspect as he grabbed for her grocery store cash register.

Ernestine Aldana, 48, was behind the counter at the San Ignacio Market when a man in a dark hat pulled a knife on her and attempted to rob the store register, police said. Aldana pulled a handgun from behind the counter on the man, causing him to flee.

"All I remember is being scared," Aldana told ABC News. "I believe if I would have had my finger on the trigger I would have shot, thank god it actually didn't come to that, everybody thinks it's easy to pick up a gun and shoot someone, it's really not."

Aldana said she was thinking about firing, but by then the suspect had already had turned to flee.

The remarkable incident was all caught on surveillance video released by the Milwaukee Police Department, which is searching for the man. Aldana described the man as Hispanic, about 35 and between 165-180 pounds with pock marks on his cheeks.

Aldana says her son, who took her to a firing range to train her to shoot, bought the gun for the store. The family never thought they would need for the firearm, but are now grateful. "If I didn't have the gun there, he would have hurt me, once I had the gun there it changed everything," said Aldana.

In December 2011, Gov. Scott Walker signed a bill passing the "Castle Doctrine" in the state, which protects home and business owners using a gun in self-defense on their property.

Aldana added that she is now skeptical of restrictions on gun ownership. "[The gun] saved my life," she said.