Hi gransky and welcome! I, too, am a new grandmother to a 10 month old (grandson) and my DIL is very close to her mum, who spends a few days a week with them. So I am very much Granny 2, although I also visit them regularly (usually every fortnight). Recently I gathered that something I had said or done had not found favour
- to be honest I can't even remember what it was now. Anyway, I feel as if I am still getting to know my DIL (baby came along the first year they were married, much wanted) and I decided to say that to her. So on one of my visits, when we were alone, I told her how it was all so new to me - being a mother-of-the-groom, being a MIL and now a granny and we ended up reflecting on and chuckling at how much had happened in a short space of time, and found some common ground about how we felt etc. I find that just by me being honest about it being a steep learning curve, has made a huge difference to our relationship and developing friendship.
I wouldn't profusely apologise if I were you, but I might say "Sorry if I mess up, I'm still a trainee granny".
Good luck! 