Mychael,

Wow this is a tough one, it is like you said Grandma, and I always felt to upset Grandma was a no-no. She did say that she really did not like you being kilted, and I would probably go along with that, however you are an adult, and that in and of itself is some merit in what you do and say.

I would go for a compromise and show up at the party without the kilt, and talk to others that you too wear a kilt (easy too do with the kids kilted), and about half way through the party change into your kilt. You have already told people that you wear a kilt, and maybe with you letting them know you can then show them what it looks like, they are already prepared. Of course I am unsure of your family dynamics, but that is how I got most of my family aware that I am a kilted gentleman.

Good luck to you what ever you decide, and do let us know how everything went. Tell your Grandma Happy Birthday for me.