I have watched the video introducing Pearl Mackie as Bill as the new Doctor Who companion and I am starting to feel a bit more sure she may be from the past like 80s potentially. Besides the fact she dresses kind of retro looking like the fact she is wearing a Prince Purple Rain shirt which by the way didn't come out till 1984 so its possible she’s from after 1984 if she is from the past. Another reason why I believe that she is from the past is when The Doctor says the year 2017 needs them he refers it as the future. Now why would he call it the future if she was from the year 2017? It makes it very possible she is from the past just because of that to me.