As for why I don’t tell her…well, let me tell you about our last religious discussion.
I told her I wouldn’t be going to church with them. I felt that their church was abusive and endorsed strongly misogynistic teachings (and named several specific examples). She admitted that I was correct in my examples but brushed them off as “well no group is perfect.” At the time she criticized me sharply but did not argue too much.
The storm came later. She asked me to justify my decision. Repeatedly. I mean several times in a day. And she wanted to go through the exact same arguments each time, because she “still just doesn’t understand what the issue is.” At some point I refused to answer any more. This got her to alternate between telling me that obviously my heart was not right because I was not only rejecting church but disrespecting my mother, and crying and asking why didn’t I love her or care enough about my family to go to church with them.
In no case do I have any reason to believe any of my arguments were actually listened to. The one time I brought up Catholic teaching she repeated several of the classic lines, and then brushed me off as ignorant and naive when I brought up evidence to the contrary. I really do think she means well, but she seems to have gotten stuck in the homeschool parent mode that she was in when I was younger - no matter what, she’s the parent, so she knows more than me and it’s my job to accept what she says as true.
I have to say, that this attitude toward adult children is not unique to home-schoolers. I went to public school, and there really isn’t a single subject about which my mother will listen to me with respect, except of course those subjects on which we happen to agree. And as to how long that lasts, I have certainly had more than one 29th birthday by now. We just won’t say how many.
Fortunately for me, my mother has a somewhat different temperament than yours. So rather than haranguing me for days about a disagreement, she just shuts down the conversation immediately and sulks for a while. In the days when I used to be stupid enough to try to keep the subject going, she would just get into a state about how everyone always contradicts her and nobody shows her respect and so forth. I have now given up ever having my ideas and beliefs respected by my mother. It’s a shame because it means she thinks we have a much closer relationship than we actually have, because I just avoid telling her anything she would be disrespectful about. Some of those things are pretty important to me. We can’t discuss politics AT ALL.
Funnily enough, one of the (less important, since I have no children) subjects that she used to treat me like some sort of idiot child about is home-schooling. She felt quite strongly that we have some sort of obligation to support public schools by sending our children there, and if that meant early sexualization of children, hugely increased access to illegal drugs, that weird “nobody understands me unless they are exactly my age” thing and whatever else, well, it was unrealistic to try to avoid any of that. I’m not saying there aren’t valid arguments on both sides, and I would have been happy to have a discussion about them with her, but that wasn’t possible, because if the response to every one of your arguments is basically, “You don’t know what you’re talking about,” you can’t have a discussion.
For you, since you can’t have a discussion about it with her, I’d listen to her views once, respectfully, letting her get them all out. Then you can respond something like, “I understand your views, and I respect you as a person, but this is my life, and I have to make my own decisions based on my own experiences. I don’t think we should probably talk about this during the holidays, because I won’t be changing my mind, and we don’t want everyone’s Christmas to be ruined. I’ll be happy if you want to pray for me, but please don’t argue with me.”
I think that if you wait until spring to tell them, your family would have some justification in thinking that you were a bit secretive with them over the holidays because you didn’t tell them. They might also think you were ashamed. But I do agree with St Francis that you do need to let them see your joy. Pray that the Holy Spirit will shine out from you and they will see your holy joy!
–Jen