Updated

The teenage mother who shot and killed an intruder on New Year's Eve after asking a 911 dispatcher for permission told Fox News on Friday that she still somewhat in shock over the ordeal.

"None of it seems real," Sarah McKinley, 18, told Fox News' Shepard Smith.

McKinley, a recently widowed Oklahoma woman who was home alone with her 3-month-old son at the time, said she focused on every little detail and noise while she was on the phone with the 911 dispatcher as the suspect broke into her home. "It helped me to stay calm," she said.

Authorities don't plan to file charges against McKinley for killing the intruder, Justin Shane Martin, but Martin's alleged accomplice has been arrested and charged with first-degree murder.

A 911 tape released to Oklahoma City media outlets Wednesday details how McKinley asked the dispatcher for permission to shoot the intruder.

"I've got two guns in my hand. Is it OK to shoot him if he comes in this door?" McKinley asked the dispatcher.

She had grabbed a 12-gage shotgun but wasn't sure if it was going function since it hadn't been used in over two years, so she grabbed a pistol for assurance, she told Fox News.

"Well, you have to do whatever you can do to protect yourself," the dispatcher is heard telling McKinley. "I can't tell you that you can do that, but you have to do what you have to do to protect your baby."

Oklahoma law allows the use of deadly force against intruders, and prosecutors said McKinley clearly acted in self-defense. According to court documents Martin, 24, was holding a knife when he died.

McKinley was about 22 feet from the door when Martin came through the door and forcefully pushed the couch that she had used to barricade the door out of the way, she told Fox News.

That's when McKinley saw Martin with something shiny in his hand, which she took for a pistol, but later was determined to be the knife. She fired when she saw him shove the couch out of the way.

"Our initial review of the case doesn't indicate she violated the law in any way," Assistant District Attorney James Walters told The Oklahoman newspaper.

However, prosecutors have charged Martin's alleged accomplice, 29-year-old Dustin Louis Stewart, with first-degree murder. According to authorities, Stewart was with Martin but ran away from McKinley's home after hearing the gunshots.

"When you're engaged in a crime such as first-degree burglary and a death results from the events of that crime, you're subject to prosecution for it," Walters said.

Stewart was arraigned Wednesday and was being held in the Grady County jail. A bond hearing was set for Thursday. His attorney, Stephen Buzin, did not immediately respond to a message left at his office Wednesday night.

According to court documents, Martin and Stewart might have been looking for prescription drugs.

McKinely said her husband had died about a week earlier -- on Christmas Day -- after being hospitalized with complications from lung cancer earlier that month.

The Associated Press contributed to this report.