Well, last week, I took little dgd to a 'stay and play' group for the first time. I had to fill out a form with some very basic details. Went again this week and discovered that I had got the most basic of those details wrong - my dgd's name!
To be honest, it was sort of her name, as it was one of the many shortened versions that her official name can have, but not one that any of us ever use. 
I did something not too dissimilar six years ago, a week or two after my first dgd (but second dgc) was born. Someone asked if it was a girl or a boy, and I heard myself reply 'a boy'! I could only put that down to the fact that, as mother to two sons and no daughters, until that point, the answer to that question had always been 'a boy'.