Step-Grandma?

My ex’s stepmom contacted me and asked me to take my 1 month old to visit her she lives an hour away but they haven’t attempted to visit me in my house (might be awkward since it’s his family and we’re not together) and she wrote she has a right to see her since she’s her granddaughter.. on the other hand my ex’s mom does come to my house to visit and always calls to see how she is. I asked my ex how he feels about me going over to his stepmom’s and dad’s house and he said no because she has always been rude to him and he told his dad he could visit us in the hospital and he never wanted to. I told him to think about it since they are apart of her life and would have to meet them someday.. should I keep insisting or leave the topic alone?