I have two horses. Horse 1 would get in my pocket if he could. He also tends to be pushy and I have to be pretty strict with him. He is the kind that will walk right up to me in the pasture all the time no matter what. Wants me to pet him, wants to be with me. But again, he's also the horse that I've had to discipline the most strictly.
Horse 2 is very obedient and I rarely have to correct him for anything. He rarely walks up to me in the pasture. He doesn't want to hang out with me. Most of the time I think he'd like to pretend I don't exist. LOL. He's not affectionate, even though I am certainly affectionate with him.
I think it really boils down to personalities. I don't think your horse doesn't like you. I don't know if you're too hard on her because I haven't seen you with her. But horses are ok with clear boundaries and it's ok to be strict with a horse. I'm sorry your horse isn't as affectionate as you'd like her to be, but I'm not sure you can change that about her. For gosh sakes don't start letting her get away with things and start giving her all kinds of treats trying to get her to "like" you more. That won't work and will only create problems for you both! Just start to see her for her own personality and focus on all the great things about her!