Girl, you are so not in the wrong. Both of them were acting super rude!
And I so feel you on the not wanting to lose friends part. I mean, I'm okay with being alone, but then where do you sit at lunch!?
But no, what they said was super inconsiderate. That's your grandma- I hope she's doing okay, truly! Watching someone close to you like that suffer is so heart breaking. But all they had to say was "wow, I want to see K-Pop?" LIKE, WHAT!? ARE YOU SERIOUS RIGHT NOW? YOU COULDN'T WAIT 5 MINUTES TO TALK ABOUT IT!?
Tbh I would've lost friends that day. I would've GONE OFF.
Anyways sorry. Kinda dealing with some friend problems myself rn. But ABSOLUTELY NOT YOU ARE NOT IN THE WRONG!
Praying for you, your family, and grandma