I have gone out, a possessed witch, (1)
Could the use of the past tense imply that our speaker can slip in and out of this possessed state? Well, that's a very good question! And it happens to be one that our speaker doesn't choose to resolve.
I have been her kind (7)
Here's where this poem gets interesting: it's no longer a statement of individual identity. It's a declaration of collective identity. Our speaker's not alone – and neither are all those other women who feel like they don't quite belong.
lonely thing, twelve-fingered, out of mind. (5)
Sometimes figuring out how to describe yourself means finding words for all those things that aren't quite so pretty. Notice how the first words, "lonely thing," set us up to dehumanize the speaker. She's not just physically strange or mentally imbalanced – she's actually a more of a "thing" than, say, a person.