Maybe this is a real lifegoal that you are set for, maybe this is a somekind of Chuunibyou idea that you just came up with playing Nier. Neither matters. Before starting any life goals, especially any life goal that consists such of a grand narrative, you need to start focusing on your present. You are a student, especially a high school student. Your ideas might change frequently, years, months, weeks, days or sometimes even minutes. As such it is important for you to focus on the present life that you are experiencing now. The goal of an "Immortality Generation" is a grand narrative that is too big for most people to bear as their life goal, not to mention that you are still a highschool student. What you need to do now, is focusing on school, your family, your friends, only consider this life goal as a minor one second to your present life. It is only when you have enough taste of life that you can consider something like that, also you're not going to be able to bear such a big grand narrative by yourself.