An 84-year-old woman died in a house fire Thursday morning, officials said. The blaze started at 10:26 a.m. in the kitchen of an in-law apartment above the garage of 304 Mill Road, said Wayne Oliveira, public information officer for the Fairhaven Fire Department. The woman, Barbara Wilbur, apparently tried to extinguish a stove fire with the kitchen sink sprayer and then attempted to exit the apartment, Oliveira said. Wilbur collapsed just feet from the door. The fire is believed to have been accidental, but is under investigation, the state fire marshal’s office said.