I did 12 years on graveyard shift, I'm 41, haven't worked in 1 year +. I still can't sleep at night. I've tried, I can't sleep until 6 am or so. It sucks. Graveyard ruined me. 3 AM , I'm still at most alert level of the day. I can sleep from 8am-6pm fine. I can't break it ! I hope it doesn't take 12 years to reverse that curse.
Moral of my story is don't agree to work graveyard shift too readily.