Mary was born in 1872, the eldest daughter of fisherman Norman MacAskill and Marion MacMillan of Borve, although whether her early childhood home was at Pol an Oir or Ferry is unclear. However, by the end of the 1880s the family were living in a newly built home at Ferry and her father was ferrying the mails.

Mary started work as a domestic servant and in 1891 married farm servant Angus MacDonald of 16a Knockintorran. It is believed that they made their home in Lochmaddy. However, Mary and their three children returned to live with her parents at 23 Borve in 1902, when the children started school on Berneray, having previously been at Achmore, Lochs. It is likely that they stayed in Borve at least 1909, when daughter Catherine left Berneray School.