Mildred's First Christmas Tree

One thing you can say
about Aunt Ethel & Uncle Harry:
They sure knew how to put up
a stylish Christmas tree!

On the back of this photograph,
my Grandmother Rovilla has written:
"Mildred's first Christmas tree
On Burn Street in Independence, Kansas"

[Mildred was born in January 1913,
so this must be December 1913]

Unfortunately, there is no note on the back of this one.
I know it is my Great - Aunt Ethel, who was married
to my grandmother's brother Harry Heideman.
But I'm not sure if this is their daughter Mildred
(born January 23, 1913)
or her sister Ila Maxine (born March 29, 1917).

Notation on the back,
presumably written by Ethel or Harry:
"Our Xmas tree this yr"
In my grandmother's handwriting: "Harry's"
~ but no date given ~

Mildred, Ethel ~ Baby Ila, Harry
~ sometime in 1917 ~