Christianity acknowledges that in a certain sense we are all born into sin (Romans 3:23 - "For all have sinned, and come short of the glory of God"), therefore for the child of an unperfected human, who is not yet perfected him or herself, avoiding sin is an impossibility. Each person is then a spiritual being who is born into a material body, and is therefore subjected to all possible material passions, desires and, importantly, fears. In our spiritual infancy and weakness, we cannot resist these passions and fears. This is the great joy of the Christian message; Christ's teachings offer a way out - a way to escape from these passions and fears and to gain spiritual strength leading to perfection and with it perfect freedom from unruly passions and fear. The message is that through self-denial our souls gain control over the passions of material world (i.e the flesh, and note, not total abstinence necessarily, but moderation at least in all things) and, through faith and growing trust in God, freedom from all fears. But like Eustace we cannot do this ourselves, we need to allow Him to transform us (including trying our best to follow His teachings and guidance).
Therefore fear not but be joyful, as the promise - for those who choose to take this path- is not death and judgement, but rather freedom from judgement and actual victory over death, as matter with its desires and fears correspond to a kind of spiritual death.
"Rejoice in the Lord always. I will say it again: Rejoice!"
PS: The Christian story of redemption - for an individual and mankind in general has two interesting related aspects. The first is what is called "The Hero's Journey". This is a common pattern of narrative, where the hero eventually sets out on a journey, gets advice from a mentor, is tested in various ways before facing his greatest fear and not mastering it, later the hero is tested again, in which he overcomes his fear and is resurrected. A simple example is Luke Skywalker in Star Wars, who is tested by Yoda (the mentor) and fails his first test facing an apparition of Darth Vader in the cave, however, later when he faces Darth Vader for real, he overcomes his fear and anger. Such 'Hero's stories' are perhaps analogies for the Christian path.
The second important story is the one of the prodigal (or lost) son. This is the son who leaves his father, squanders his inheritance, but is welcomed back with open arms - such is the story of God receiving back any of His lost children, should they choose to return to Him.