There is an alternative explanation to her seemingly aggressive behavior.
First of all, hens aren't aggressive for the same reasons roosters are. Most of the time, when a hen pecks you, she is trying to get your attention. All chickens communicate with their beaks. They discipline those lower in rank with a quick peck to the head, but they also peck each other softly during mutual preening sessions.
Some hens are more fixated than others about tiny freckles or warts on your skin, and they'll peck at them. Have you examined your feet to see if you have anything that might invite a hen to investigate it? All exploration and investigation of things occur with their beaks.
From your description of her following you around everywhere, it's quite possible your hen is quite fond of you, and is pecking you to get your attention. Next time she does that, try picking her up and tucking her head under your arm, and hold her close. If she relaxes right down and doesn't struggle to get out of your arms, then you have a hen who only wants to be cuddled, and she has been trying to let you know this.