Isn't a Mummy an embalmed corpse from Egypt?

When I enrolled my daughter in pre-school here in London, they asked if I had any special requests. Yes, if you can please refer to me as 'mommy' with her and NOT 'mummy.' The nervous laughter that occurred once I said that told me they were a bit offended...but I didn't care - I want to be mOmmy, not mUmmy...I'm sure they would want the same if they were in the US. I don't expect they are really doing it and for now, my daughter knows the difference. However, I am going back to work full-time after the holidays which means she will be in full-time preschool. Hubby thinks she'll have a full-blown British accent within a couple months of full-time exposure. Ugh - the day she calls me 'mummy' is the day I wrap myself in toilet paper cuz that's what a 'mummy' is to me!