She grew up a hour away from Reykjavik in rural Iceland. She moved away from home at a young age to go to a new school in the city. Her grandfather was the stage manager for the national theater of Iceland and she spent a lot of time there as a child. Lilja graduated with a B.f.A degree in acting from the Icelandic academy of the arts in spring 2009. She works both in cinema and theatre. She started her own theatre and production company in 2011 with a couple of friends an colleagues called Sudsudvestur or Stillweatherproductions