^Yeah but its telling a story it isnt just art. The story has to be consistant to its reality and make sense if we are to take it as more than nonsensical rubbish.
Realism isnt optional in writing unless you establish why it doesnt have to be, and even then it has to stick to its established rules.
The thing is, you're using our world laws of physics to explain what's most likely magic, the moment a half human talking cat showed up, the rules you are trying to apply don't have to apply, saying it crudely what I mean to say is "It's magic, I don't have to explain s***" .
If what you're trying to prove is whether she's delusional or not based on the kid's size, I get what you're trying to say but this "cat" is too smart, walking in on her own, she can use forks and chopsticks... So, at some point in time, someone was in front of her eating with chopsticks, not a normal cat haha
There was this manga called Ayakashi ko, axed btw... But the protagonist was able to touch the spirit but normal people could not... So at the same tme something was there and not, that's the spirits power...magic