Milk Shake murderer

I think it's dumb that she is getting a retrial. She admitted to killing her husband and all the evidence pointed to her. Shes getting a retrial because she claims it was self defence? she killed him by hitting him in the head with a metal ornament while he was sleeping, after she poisoned his milk shake, how is that self defence? she rolled him up in a sleeping bag, towels wrapped around that, then a carpet, then plastic sheets tied with ropes and tape, and then 4 cushions secured by tape. A person wouldnt wrap a body up that good and leave it in your storeroom for 4 days if it was self defence, to me it sounds like she is crazy and should get life in prison with no parole.