Her English-born mother, Sarah (born Morton) gave birth to her in Belmore Barracks.

Her Scottish-born father William Brewster was an armourer and they already had nine children when she was born.

[5] During her seven years at the school she established plants into a designed garden, she put books in the library and pictures in the corridors.

[1] Brewster died in Sydney's Royal North Shore Hospital in 1957 and in October 1958 a library was proposed and a public appeal launched.

[6] In May 1965 the Head Deaconess of Hornsby School dedicated the Agnes Brewster Memorial Library to her.