Hi Frilly,
There are two points here - the issue, and how you deal with it.
You can't change the first, but you can change the second.
Send out the text I advised - or a version of it, and than know that you have done your best.
You have a perfect right to do as you wish for Christmas, whatever your reasons, which are completely understandable.
If people go against your request, that is for them to deal with, you must simply learn not to be so upset about what people think of you.
If your family insist on going against what you have asked for, it shows a lack of consideration for your feelings, and more importantly, a lack of respect for you as an adult.
If they behave in this way, it indicates that your feelings are being over-ridden by their desire to follow the formula for Christmas, and go entirely against the spirit of the thing by behaving badly towards you.
These people do not deserve your worry and fear of upsetting them - they are perfectly willing to upset you it seems.
Send your text, don't answer your door, and enjoy your Christmas as your own circumstances dictate, and let the rest do as they want.
But on no account worry about what they think - they don't worry about you!