My first thought was that she looks quite young.The large bow & ringlets indicate 16/17.
A date is a bit more difficult but I would suggest late WW1 up to about 1920.
My only concern is that they both appear in evening wear & look like a courting couple.
16/17 would be considered very young to be dating.
Could he be a relative?
Now I'm going to add to the confusion & say it could be just pre WW1.
Older women also had this style of hair & bow at this time & she appears to be wearing a wrap around dress which was a popular style from about 1910-14.