Congratulations ! Why don't you tell your daughter-in-law what you have told us?
You would love to help when the baby comes, but you don't know what your DIL would like in the way of help and that you are concerned that you might hurt her by doing things that she would have loved her mum to do, or doing them differently from what she expects.
Right now, she probably has one idea of what she will need and want of help and when reality kicks in, she will see things differently.
I tell young mothers that I am here and would love to help or advise IF ASKED TO DO SO, but I have no intention of becoming one of the pestilential know-it-alls some grandmas turn into. Make sure your son and his wife know that you are there, they only need to phone and certainly offer to help, but don't just turn up unannounced or start doing things when you visit. Ask whether you should wash up, etc. They might just prefer to sit and chat with you.
Angela Rayner lashes out and calls Sunak “pint sized loser”.