What is the difference between non-existence before birth and death after life?
There is none. What will happen to me after I die and what was happening to me before I was born are equivalent questions - it’s timeless eternity on both sides. The only difference is that the first question carries fear and the second does not, which means that the fear of death is illusory, for how can you be afraid of what you have come from? All fear of death is in reality the fear of life.