Her father was the local schoolmaster, Thomas McEwen, and her mother was Eliza Gray (born Mann).
[1] Preston was educated at Alexandra College before going on to gain a masters degree at the Royal University of Ireland in modern languages.
She returned to work at Alexandra College and from 1901 she was employed as an assistant to the head teacher, Henrietta White.
[2] In 1932 Henrietta White decided to retire and Preston reluctantly agreed to take on the role of head.
[2] Preston died in the Rathgar area of Dublin at her home in 1951.