Muñoz will be arraigned next week before 3rd District Judge Elizabeth Hruby-Mills.
According to charging documents, Angela Barnett was crossing 5600 West and 4005 South in West Valley City on June 10, about 9:15 p.m., with her 9-year-old daughter by her side and her son, Gavyn, in a stroller.
The area was poorly lit, police said. There was no crosswalk.
As the mother moved toward the sidewalk with her children, a car crashed into the stroller.
The impact sent the stroller and the child inside it flying into the road.
Gavyn Barnett was taken to Primary Children's Hospital but later died from his injuries.
The car stopped briefly before continuing on, the mother told police.
The case went unsolved for months.
Eventually, police received a tip from family members of Muñoz's ex-boyfriend, who told police that she was responsible for the crash.
Muñoz told detectives that she had forgotten to wear her glasses that night. The road was dark and she "couldn't see very well," according to charging documents. She hadn't noticed anyone crossing the street.
After she realized she hit someone, she told officers, she "stopped her car, looked into her rearview mirror and saw a stroller," the documents state, "but got scared and drove off."
She never called police.
Muñoz remains in custody in lieu of $50,000 bail.