mahon was raised in toronto, ontario, where her parents were both choral directors. she sang with the girls' choir of grace church on-the-hill and later the oratory children's choir. she initially began studying piano, but switched to organ in 2005 after hearing the toccata from "symphony for organ no. 5" by charles-marie widor. mahon won a scholarship from the royal canadian college of organists to begin studying with melva graham, and in 2007 continued under andrew ager. she received the degree of bachelor of music in organ at the university of toronto school of music under john tuttle.