She screams arabian to me. I have to disagree with you guys, I actually think her muzzle looks very arabian.... her nostrils are small and delicate, her muzzle is round. Her eyes are also very arabian to me. Add that to her arabian- type movement, and her light build, she definitely looks at least half arabian. What makes me think she might have something else, like, say standardbred, is her body's silhouette- The long back, high withers, and camped-out back legs make me thing of a standardbred. I have to say that I agree with Nokotaheaven on her probably being 3/4 arabian, and maybe 1/4 standie or saddlebred, maybe.
But I would not rule out the possibility of her being full arabian, not at all.