Born in Vancouver, British Columbia, Erin and her older sister Kim and younger brother Trevor grew up in South Vancouver, and then Surrey, a nearby suburb. Erin's parents, Ken and Lynne Sterling, worked for the local taxation centre prior to retirement, although Ken was originally a teacher, and then a sales. Erin became involved in drama classes in junior high school, and added involvement in local theatre while still in high school.
Erin graduated from Simon Fraser University in 1994 with a Bachelor of Arts, majoring in English and minoring in Women's Studies. She graduated from Vancouver School of Theology in 1998, earning a Masters of Divinity; here she met her partner Edward and they married in 1996. While sharing in ministry and parenthood, Erin and Edward lived in Nova Scotia and then Manitoba, before returning to BC in 2007. Erin became involved in local theatre while in Manitoba, acting and directing.
After moving to Vancouver Island in 2007, Erin began studying film acting at the Screen Actors Studio in Victoria. She earned her first credits working with local independent filmmakers. She continues to study at the Studio, participate in theatre and act on film.