Short answer is NO!
If you shave it...what will it accomplish?
If you are shaving so she will not talk about jw religious beliefs, then u are the only one making a personal adjustment.
Your age may dictate what you do to please your mother...based how much control she has over your personal decisions.
I kept my beard on, although it was neatly trimmed. My mom quickly got over it with some talk about how many have a beard this day and age. Even JWS.
It is my experience most mothers are not going to throw a stone at their own flesh and blood unless their attitude is offensive. Your mom may be different.
So to me the decision would be, what affect will keeping it on have on the visit? Will u feel uncomfortable? Then shave it so the time spent will not be causing tension.
SW