I suspect the image may be reversed
I've been caught out like that before so looked at the buttons as well. 
The only way this would be in reverse is if this was a Tintype which it isn't so is this European ?
jim
The watch is also on the 'wrong' wrist. It's an odd one this! I agree with Jim re the date but the skirt is a bit short for pre-1920 and the hemline is very uneven. Also, the small cap. Shoes have ribbons as laces

Hair is up and she looks between 18 and early 20s to me.
Could the clothes be photographers' outfits?
Gadget
PS - is that a coral necklace - it looks like one that I have?
and when were those patterned stockings fashionable?