One of Carmichael's paternal great-grandfathers was aviator Captain Norman Blackburn, a British pilot and flying instructor during the First World War, and afterwards a Director of Blackburn Aircraft. She was educated at Shirley Junior School, The Mountbatten School, and Peter Symonds College. Carmichael attended the Bristol Old Vic Theatre School in Bristol, graduating in 2007, before spending two years in various odd jobs, including a teaching assistant, receptionist, and nanny while going to tiny auditions in fringe theatres.