My greatgrandmother died on my mother's 8th birthday. My grandma, for several years, didn't celebrate my mother's birthday. They are all dead now and I cannot ask my grandma why she didn't move the celebration onto another day?? But it was her wrongdoing. In your case, you stopped your mother from hanging the Christmas ornaments, which shows that you internalized, absorbed, and amplified the guilt very early on...

My mother blamed me for shortening her life, saying that had she not been nervous because of something I did (which was something she herself suggested), she would have reported her breast lump right away and not waited a year.

My ex 2nd H blamed me for the death of his mother (at close to 90...) because he claimed that I had ruined his relationship with his ex boss, an influential woman who, in his mind, would have been the only person able to find a good doctor when his mom fell ill.

I got so used to being blamed this way that when Maddy, a young kitty, dropped dead last August, I felt responsible. My bf and two old time guy friends who care about me were all saying that I think like a prehistoric woman. T said that matters of life and death are outside of our control. The vet explained that Maddy must have died from a painless sudden heart attack, as there are no other reasons for a healthy young kitty to drop dead without warning. So it took 5 people to make me relieve myself of guilt.

I am not trying to trivialize your pain, which is clearly far, far bigger than mine, but just showing how easy it is to assume guilt even in situations which are lightweight in comparison with yours. Guilt is such a sticky sticky thing...