Shanmuk

i always wonder that if our previous life karma brought us to this life and so on, then there must be a start as in first life where we did not do any karma.then why were we born in the first stage? god is the supreme being-true.but when he is the supreme being why does he have to start a life form to gain experience? i am not trying to contradict anything but these were the doubts i have been having since the age of 5.