We are genetically hardwired to avoid death. Its what we are meant to do; survive, adapt, spread our genes, and surpass our conspecifics and/or other species to fulfill our own niche, as best as possible.
Unfortunately its very hard to remove that instinctive fear of death. Its very natural, and normal. I know many individuals, some even on this very forum, insist that they do not fear death, but I don't believe it. When faced with life or death, one will always be stricken with fear, until they have no other choice but to endure and accept it. When we accept death, our mind dies.
Death is a natural course of life. Without death, there is no life. Our energy is then used to feed the ground, plants, and other organisms, until it manifests as another entity. That's what I believe, anyway. It is scientific law: energy cannot be created nor destroyed; only converted into other forms. We've been on this Earth longer than we could ever imagine. It is natural to fear death, but it is something you've experienced time and time again.