The incident occurred at about 6.45am as the house help walked back home after escorting two children to school.
According to police, the woman was shot when she barred the gunmen from entering the compound where she lives.
Kayole Police Chief Ali Nono told Capital FM News that they were investigating the killing, which is said to have been committed by known criminals in the area.
“They were two gunmen and we are pursuing them to ensure justice prevails,” he said.
The 24-year-old woman was shot in the head and died instantly.
“I still don’t believe Florence is dead…we were with her but luckily I escaped the wrath of the evil men,” a teary neighbour only identified as Sylestia said.
Elsewhere, two suspected gangsters were on Tuesday night shot dead in separate incidents in Nairobi.
One of them described by police as a notorious gunman was shot in Dandora by his accomplices during an argument over stolen money.
The slain gunman identified as Kamaa is said to have been part of a gang that had stolen an unknown amount of money from a shop in Kariobangi on Tuesday.
Police in Nairobi said the slain man was wanted for a series of robberies, murder and carjackings in Eastlands.
Another suspected gangster was shot dead by police in Eastleigh and a firearm recovered.