As soon as people know you are going to have a grandchild - everyone starts asking: "What is he or she going to call you?"
Some people cringe away from the word "Grandma" Like having it used in reference to them will somehow magically transform them into some gray haired, stooped over, ancient granny type.
Whatever... I don't care who calls me Grandma. It's just a word. I do have a grandchild, which does make me a grandmother no matter what I am called.
I will confess that I prefer that the Little Guy call me something a little more unique and with a little more personality to it. Not because I have some deep rooted hatred and/or phobia about the word grandma. Just because I like to spice things up a little. I don't want to be just another Grandma in the world.
Also, in our family every grandmother has ended up called something different, which helps to differentiate between them. The Man of the House's grandmother is "Grandma". His mother is "Nana". My Mom is "Granna"
I have been liking Oma (German for grandmother). Honestly, at this point the Little Guy could call me just about anything at all and I wouldn't care!