So, should i go to my friend's house or not?

Ok, so one of my friend(A) is going to my another friend's(B) house to do their assignment and they invited me since i live close to them. The problem is that B's parent are very strict, and i just got braces a while ago and i still can't chew hard things, and i was wondering, what if B's mum make lunch for us while i was over, and i couldn't eat it because of my braces, wouldn't it be very impolite and rude? And also, A is there to work and i'm not so i don't really know what to do. Another thing is that A said if i don't go, then She won't go to my other friend's( C) house. And C really wants A to go. So what can i do?
The thing is that i actually don't want to go but due to the above reasons, i don't know what to do.