It is her step daughter that has had a baby, but we dont do the whole 'step thing' in my family really, (apart from with them being her stepkids) as such!
And she is a hell of a lot more of a parent then her step daughters dad has ever been!
I became a great auntie at 21 when I married my husband. His nephew and neice are older than me lol Not that I'm known as Auntie even if I am married to their Uncle!
to be fair, my grandson's mum is only 15 years older than him, I'm going to ask her tomorrow what she would do if he made her a great grandma at 39, i struggled being a grandma at 44