This is a little hard to confirm from me, but the PIXIV comments may suggest this could be Cirno dressed as a maid. Can someone confirm this?
-Eidt-
Thanks for confirming this.

Artist added tags have Cirno. Therefore, this actually is Cirno.

Oh my - this is truly adorable :)

This looks more like a blue-haired Sakuya than Cirno to me (no offense, but Cirno has those icy wings on her back).

It's not surprising where you see a lot of images by artists where a character doesn't have a particular feature (e.g. Aya's wings, Cirno's wings, Ran's tail etc).