I'm going to come out to my family at my grandfather's birthday party.
Why are you choosing such a random occasion to come out?
Because I'm fed up with holding my real identity back
While it may come across as a little rude to make someone else's event about you, I understand that holding back an identity is probably really tough. If you think the time is right to come out then go ahead and come out wherever you deem fit.
Thank you, I have been preparing myself for this day for quite some time.
Coming out isn't easy and I wish you the best of luck. While this will make your grandfather's event more about you, it isn't a bad idea as all of your family will be gathered together in the same place and you can tell them all at once, which might be a bit easier.