Apologies for how long it's taken me to get to review this!
So I checked out your other poem, too, briefly, and I think you have a really good gift when it comes to flow and rhythm. I think this is what's really driving your poems, but I also think that there are some things you can do to shore up the rest of the work. First off is the use of imagery. You have a few images in your work, but I feel that you can add more - especially in this one. Red Pill, Blue Pill seemed a bit more alright to me without the imagery considering the subject matter, but I think part of that might have been because I was reading the Matrix into it? So the need for a mood was less present for me, I think, because I was relying on a previous construct for that. This poem, though, needs the imagery a lot more I think. As said, you've got some images of the girl, but I wanted a bit more of an understanding of setting because the new girl's walking and then the old girl's sitting and I'm not sure if the old girl's supposed to actually be there or be a memory or be a hallucination . . . I think some clarification of the setting of this might help with that issue in particular by either setting the old girl (sorry if that's bad terminology, lol) in a flashback or in the present day. I think you mean her to be projected onto the new girl, but it's not as clear as it could be and, while perhaps some confusion about the situation is an interesting approach, I'm not quite sure it's working for me right now because I want the narrator to be confused but not necessarily have the confusion extend up to me as a reader. Does that make sense? I think maybe some of my confusion comes from the fact that it sounds like the new girl is walking away and then suddenly she's sitting, so I need some in-between actions or to be able to extrapolate from the surroundings that the girl is supposed to go back to sitting again (for instance, a function like a Mass might convey that easily.) She's just kind of floating right now, but the new girl should be anchored and clearly real while the old girl and the connection to the old girl should be a bit more ethereal. It's a bit blurry right now.
In regards to other imagery in the poem, I think 'purposeful walk' and 'flowing hair' are working for me, but I kind of want to see this girl more since she's the subject of the poem. Perhaps you mean it to be vague, but I was craving more details and more powerful words, since right now I'm not sure you're quite establishing the right mood. You have a lot of plain words, especially in regards to verbs (I mean these: is, was, were, are, had, have, has, do, does, did, seem, feel, etc.) I'd encourage you to try to push for more particular, accurate verbs and nouns - especially verbs. As the powerhouse of the sentence, they drive the emotion and craft the mood. 'I had a dream about you last night' is much different from 'you crept into my dream last night.' (Just a suggestion, by the way, I encourage you to find your own words, of course.) 'Crept' tells me something about the girl and her movements, that this was a furtive action and perhaps unwelcome or unwanted. It sets a mood better than 'had' because of these assumptions I make from the usage of 'crept.' Choosing the right verbs can lend a lot to your imagery and characterizations, and I think it may be the root of why I want more description of the girl, because many of your verbs aren't doing the right amount of work for me. 'Deceived' is the only one that's making a strong statement to me. If this poem were of a different subject matter, perhaps plainer verbiage would work, but I can tell there's real emotion here, real pain, and unfortunately it's not quite communicating to me yet. I enjoy reading this, but I'm not being necessarily drawn into the narrator's emotions, if that makes sense? I'd suggest really focusing on your word choice in order to establish mood. In your other poem I read there was some of this, as well. Just experiment, you know? See how new synonyms either help or hinder your rhythm and if they contribute more to the mood. Poe would be one to look at for a great example of mood, Maya Angelou and Pablo Neruda, as well (though I daresay many famous poets are successful because they know how to manipulate mood.)
If you're not sure that you want to buff up your verbs, I'd suggest you consider using other poetic devices (repetition, especially) to really amp up that beautiful flow you have. You do some of this successfully already, but playing with it more might lead to some interesting results. If you just look up 'poetic devices' on google you can find a worksheet with a lot of different options to explore. This poem by Pablo Neruda is an example of supplementing rhythm for strong verbs: http://www.poemhunter.com/poem/a-dog-has-died/ He obviously uses a lot of adjectives and nouns to establish his imagery, but I figured it could be a helpful example.
Obviously, whatever you do is your choice, but I really like the way this flows. It has power even if the words aren't quite hitting my emotional chords the way I want them to. It also looks nice! =P At any rate, I would at least urge you to broaden your word choice and to experiment with synonyms and imagery. Try not to rely on cliches ('flowing hair' is a bit of one) and definitely ground this more. Good luck with your future work! Let me know if you have a revision of this you want me to look at. =)