Advice: Should I attend Christmas Mass with my family?

I’m going to try to make this brief but also provide a little bit of background information. I’m 27 years old and was raised catholic by my parents. I was baptized, had my first communion and confirmation, all by the time I was 10 as was the custom.
The other day I was talking to my parents and my mom mentioned that my brother would going to church (he is younger than me and still lives with them) with them for Christmas eve mass. I’m staying with my parents on Christmas eve since my boyfriend is out of town and I don’t want to stay at my place alone. I told my mom that I wouldn’t be going to the mass with them and she questions me on why. I told her that I don’t consider myself catholic. She asked me since when, and I told her it had been a couple of years. That is wasn’t something that I just decided, it was a conclusion that I came to over a period of time by reflecting on my feelings and ideas. I told her I believe in God, I’m not an atheist, and I do prayer sometimes, but that I don’t believe in practicing a religion. She was clearly upset about it, but didn’t really react, still I know her and I could tell.
Without going too much into it, I’ve never truly felt at place in the church, being gay, but despite that I just don’t feel a connection to it, and I don’t see eye to eye with some of its stances. Religion is not something that provides me any comfort or support, despite being filled with many great people. Belief in a high being, God, does, but not religion itself.
I’m not here to be convinced to reconsider, I’ve already come to my own conclusions, but I wanted to give a bit of back ground so that you know where I’m coming from when asking this question.

My mom said to my brother, before I had said anything to her (I only found out after when he told me) that it was important to her that we all go together. And I considered that. I thought about it before my brother even mentioned this, that it is probably important to her. I respect that she finds comfort in it and that it’s a part of her, I would never try to convince her otherwise, but I think she should also respect that I don’t practice and that it’s not something I believe in. I know maybe it will take her time to get over as I never really mentioned it to her before, it’s not something that ever came up. But I’m an adult now, and one who no longer lives at home and hasn’t for 7 years. I haven’t gone to Christmas mass 2 years since I’ve spent Christmas with my boyfriend. And I haven’t attended a regular mass in even longer.

So what are your opinions? Do you think it’s rude of me not to attend the mass with my family? Or is it unfair of her to expect me to attend? Or something in between.