It is lovely, but maybe we can have a few more clues. If you can please measure the length of the blouse, from shoulder top to hem in front, that would be helpful. Also, can you show a close up of the cuff, and the sleeve in its entirety, laid flat? Do the cuffs fold back? It looks both WWI era and 1930s to me, so these clues might help determine it better.
Ohh...the cuff does fold back because the stitches. The shoulder top is 14 inches and the length is 15.5 inches.