We ALL partake just as the first christians did.
Yes, dear PSacto (the greatest of love and peace to you!)... because, in addition to ALL who left Egypt eating the manna and drinking from the rock-mass that is Christ (1 Corinthians 10:1-5), Peter (one of the 12, of which Paul was NOT) said:
"The blessing is for you AND for your children." (Acts 2:39)
Your mom is suffering from a very common JW "malady", dear one: having a FORM of godly devotion... but proving false to its power. What is its power? Love. The greatest power. Because love... NEVER fails. Even as to one's enemies. Unfortunately, your dear mom doesn't know this because those who've taught... and continue to teach... her, don't know it.
YOU, though, do not let anger, pain, or anything other thing separate YOU from the love... that is in Christ. Even love for YOUR "enemy."
In that light, not only MUST you keep praying for her, but perhaps next you might consider showing your mom the love she is unable to show YOU... and attend her event with her. You (and your family, if they go with) should partake, of course, because that is a demonstration of YOUR love for Christ... as well as a potential example to be set for her. if she protests, show her what Israel did in the wilderness, what Christ said about "anyone" eating and drinking and NOT stopping the little children from coming to him... and Peter's words about who the blessing is FOR. The decision is yours, of course, but we of the Body MUST remember that it is just as much upon us to show the world love... as it is for them to "do good" to us.
I hope this helps and I hope your pain is brief.
YOUR servant, sister, and fellow slave of Christ,
Shel