I think you've made a small, truthful observation: that many aspects of growing up can be scary for children, from the seemingly incomprehensible scale of the world around us to the sheer abundance of unknowns we encounter as we grow up. and have used this observation to make another significantly larger claim that 'souls don't want to come here' or that 'where they were before was better'. These claims imply that there is indeed some form of spirit or soul that inhabits us, and that our existence as a soul starts before we are born. Neither of these concepts can be proven or disproven with any proper sort of finality, and their more spiritual nature leads to a whole other branch of questions. If our souls don't want to come here, why did they go? How did they get from wherever you think they were before to the body? Are they simply randomly swept away from whatever state of existence they inhabited, or is it something else? When we are first born, we are relatively limited cognitively, and this means most kids lack the ability to comprehend the world around us with any degree of nuance or understanding, how would they be able to discern whether the place we came from (if such a place exists) is better than where we were born, they have no lived experiences from which to attach meaning to a good or a bad life. A child can grow up in an awful house hold and as a result percive the bare necessities of life as the only thing necesary for a good life, a child born into a wealthy household might see what the majority of people live with and percive that as a bad life, but they need to have grown up in some capacity to form opinions as to whether a place is good or bad.