Memory of a cat

I like cats. When I was a child, my grandma fed a cat. It was as old as me, however its real age must be very older than me for a cat, it/she must have been much older. She accompanied with me in throughout my childhood, and, when I was 12, she disappeared in on a rainy night. No one knew where she had gone. I looked for a long time but couldn't find anything. My grandma told me that the cat was very old, so she knew her life would end (this is technically correct, but it's more natural to say, "knew she/the cat would die soon").
I had to accepted (use the infinitive here) this and, from then on, when I saw any (or "a") cat I would memory remember my cat, also and the days (or "time") she with me.