This is a bit weird, but I seem to have this completely irrational hate for this person...?

Hate is a strong word, not to be used lightly, I don't think you can really hate someone that you know so little about so I would describe it as strongly dislike. Your friend could have a strong case here I think, Its a bit of an immature school yard attitude to take but the mind is an interesting thing and I was drawn to you question because I think we all feel like this about others sometimes even though we know that we probably shouldn't. Perhaps it's an intuition and there might be a chance that she isn't a nice person and an internal instinct of yours is telling you to keep clear for your own safety. I think it is more likely that its a paranoia problem of yours to be honest and you should give her a chance, first impressions are often wrong and that's when it can turn to bullying if you are not careful. Don't be afraid of someone just because they are different to you, and remember that you have to accept that you can't get along with everyone in life sometimes personalities just clash so you will just have to be civil to each other when you have to work together. Its the same all through life i'm afraid. Tolerance must win over personal insecurity.