Chemo and being sick help?!

I got a cold on Saturday night and am still pretty sick with a cough and congestion. My MIL is currently doing chemo for her cancer. It’s almost thanksgiving and I feel so sad about this but I feel like I shouldn’t attend their thanksgiving dinner. I don’t want to get her sick right now. I know it’s still a couple days away but I feel like I just shouldn’t attend. What would you guys do? I’m sad as this would be all of our first thanksgiving together but it’s not worth her catching my cold.