granny?

I came across this old photo this morning, while having a sort out.  I can't remember if it my mum's mother or her grandmother.

My mum was born in 1912, so this young woman could be Edwardian.  If it's my great-grand mother, then more likely Victorian.   

Perhaps a passing blipper might be able to throw some light on the style  of clothes or the photographic technique.  Just curious.