Dear Diva,
I was wondering if the person who asked you not to attend understands what you go through? Perhaps they knew how difficult it would be for you. I would really give this some thought and try not to assume the worst in this situation. We all know that in a time of grieving people do not always stop to think about what they say. We get wrapped in our own pain and can easily forget what others might be feeling.
Diva you know from our chats some of what I believe in so I don't think you should feel bad that you are somewhat relieved you do not have to go. I think your Grandma would understand. Maybe on the day of the funeral you could choose to remember your Grandma in a way she would appreciate. Play her favourite music, do something you know she used to enjoy, or write her a letter about how you feel.
Celebrate the woman you knew and loved.
Try to be gentle with yourself and take care.