Well, it seems obvious to me that she said "someone" at that point because it was BEFORE the realization. You can see that something interupts her thought in the second to  last panel on page 23. That could be when she recognized the fighting style and THAT led to the realization that BW is Kate. Or, it could have just been because this hot woman turned and looked at her. (She was, ahem, admiring BW before anything else entered her mind.) The ironic thing about this discussion is that I agree she recognized Kate. I also realize that it's not stated because it's written to be another "clue" to Batwoman's identity.