no its not crazy. a lot of people believe in reincarnation (belief that one lives many lives and upon death is reborn as new people, plants or animals).
I find the concept quite fascinating myself. Right now Im reading the fictionalized book the reincarnation of peter proud thanks to one of my clients.

if you go to the library and research the topic of reincarnation, past life regression you can find many studies and documentations of people, religions that hold to the belief of being born again / reincarnation. its amazing how many documentations there are to how some people have supposedly come back time and time again being related to or within the circle of friends of the same people, possibly to right wrongs, relive and better their lives.

just imagine what if there is more to death and dying besides just the end. imagine being able to come back in a next life time to make changes that have gone wrong in this life time.

some people and religions believe in God and other higher powers, and others people and religions believe in reincarnation. in my opinion its all good.