'Grandma' or Gran is by tradition used for the maternal side- the baby's mum's own mother.The term 'Nanna' ,or nan,nanny,is traditionally given to the paternal side- the baby's Dads own mother.Maybe that's why your daughter said she won't call you that? But then that wouldn't explain why she's using 'grandma' for her boyfriends mum?- Has the boyfriends parents been asked what they prefer? (Grandad/grandpa is same whichever side) Or were the names used by chance first by the boyfriend? Next time they come round, stand next to them and wave a hand between you &other 'gran' and say "well what name AM i having then?just so we can differentiate between us both??" Explain about the traditional 'Nanna/Grandma' labels, and let her decide then, you might be surprised to find the boyfriends mum prefers the traditional 'nanna/nan/nanny' and is happy to swap. Or if not ask your daughter outright what the little one IS going to call YOU then? Has your DD always called you 'mum/mother' or does she refer to you by your first name at all? That could be the crux of it.As others have said, the child, once speaking may well have its own 'special' name for you- as kids we used the traditional names, but my sister couldn't say it so called our mums mum 'gran' & our dads mum "grammy"- i myself have sons kids who call me Nanna and 2 Daughters kids call me Grandma.Try not to let it spoil this time for you, but you DO need to know how to refer to yourself, or for others to refer to you, regarding your GC, as years down the line it will be too much of a mouthful (if youve to ring school for example?) "Oh, im 'so&so's (childs name)mums mum!" 