Did I kill my hamster and should I feel bad?

I had a hamster years ago called Tilly. All my other hamsters lived for about three years but she was only one year and I just found her dead on the floor of the cage. She had a two story cage and my husband said she might have fallen and hurt herself. I often think about it and wonder if it was my fault she died when she was only one year? I did all the things you're supposed to do and I feel guilty about it even now. Can somebody say something to make me feel better?