They all give good, sound advice.
And trust me, no matter how much knowledge you acquire can compare to hands on experience. Begin with the basics of grooming, or even visiting inside the pen. Get to know the horses, and bring them apples or carrots.
In the beginning, I was just like you. Had this terrible fear even though nothing had directly happened to me. But then you learn to respect the horse for what it is. And a big thing is to not feel smaller than the horse. They are large, powerful creatures, but they will feel as big as you let them. If you begin to view yourself as a "larger" creature, then that confidence will show. Also, don't let them in your "bubble". Say you're grooming them or visiting, and they start to get pushy, get pushy back. Don't let them control you. It's easier said than done, but with practice, you'll get your confidence back! :)
Confidence won't happen overnight, but if you take baby steps (like you plan to) then you'll be miles down the road before you know it! :)