She looks like an Easter egger to me. Her comb isn't a nice pea comb like a pure bird should have.
she could be a poor quailty white Ameraucana, though. If she has white skin (on the bottoms of the feet is the best place to get correct skin color) and lays blue eggs, feel free to call her an Ameraucana. Just know unless you know her parentage she may not breed true.
I have a solid white bird that looks exactly like a white Ameraucana, I'm just waiting to see what color egg she lays. Thing is, I've never had a pure Ameraucana hen, so I know she can't really be, she's a recessive white fluke from someone else in my flock. I'm going to enjoy her for what she is, but she won't be in a serious breeding project.