How long should the grieving process last?

A long as needed when someone who you know and love has past away there is a hole in your life your mind needs time to adjust to the new environment it is not abnormal to greave longer than your peers it just means that you loved them so much there us a too bigger hole I know this because I am 11 and my nana past away when I was 7 I still miss her terribly hope I helped you