I think we all, especially as we age, need to be very careful that we don't contiinually talk about our pet interest, whether this is grandchildren, cats or anything else under the sun.
No-one quite honestly wants to hear all about my marvellous clever cats morning, noon and night, or DH's poor health or whatever.
Wanting to share your pride in your grandchildren is natural, but please do remember that the very topic can be painful to those who do not have children or grandchildren and would dearly love to have had them and to those who are estranged from their families.
If you don't even know what your friends' interests are, as I infer, perhaps unfairly from what you wrote, it is high time you tried to find out, otherwise you are quite certainly boring to try to talk to.
Water Pollution -“ A National Disgrace”? A case for renationalisation?
Is it me or am I getting mixed messages