Hello. I wish you success on your journey. It is a very noble decision, and by all accounts one that will be difficult, but certainly worth it! I hope you always are surrounded by people who respect the incredible courage it takes to obligate yourself to all that is required of a Jew.
I highly recommend listening – don’t just read it – to this topic on the simpletoremember website, starting with the audio of Rabbi Lawrence Kelemen. I think it’s called “the real meaning of christmas” or something like that.
I hope that by the time you actually convert, your dilemma will be expressed differently:
Not, Is there a way I can celebrate the “non-religious, benign” traditions, but rather,
What should I do? I don’t want to hurt my family, but I have followed my intellect, and concluded that the Torah is the absolute Truth. How do I handle situations where my belief that there is no Truth other than the Torah, could appear to be sort of, slightly, negotiable? (either overtly, or passively)
Regardless of what secular people say, there is meaning infused in this day (even though it is a bunch of baloney, historically). It has become a celebration that claims to commemorate the birth of a movement that claims to replace the holy G-d given Torah, with a “New” arrangement. In simple terms that is heresy! It is a rebellion against what G-d said! The thought of participating should become very distasteful to you. Your intent to convert to Torah True Judaism, by definition implies that you will invest meaning into your days, one meaningful hour at a time!
Part of the challenge that you are taking on, most likely will include upsetting family dynamics. You will have to compensate by developing other occasions to celebrate your relationship with your genetic family (as guided by a G-d fearing Rabbi). Perhaps it will mean making a very big deal about birthdays. As you stated, your decision has caused a lot of pain in your family. That is because you ARE rejecting much of their approach to life, and the underlying belief system in which they function! You are choosing truths that do invalidate theirs. Apparently you understand that following Truth, and coming closer to G-d, overrides the pain that it causes your family (which is highly commendable, as expressed clearly in Megillas Rus – The book of Ruth). Your first obligation is to your own neshama – your Jewish soul.
Again, I wish you much success along your journey, and may you always be respected for this courageous life-changing choice. When your conversion is considered complete according to halacha, imagine my voice calling out a thunderous MAZEL TOV to you!