This was a very cute chapter indeed! I loved it.
Kase is only human, she's insecure and stuff too, eh? Yamada didn't just knuckle under and accept her demand/request, that's a very good sign in a relationship. And yes Yamada is an adorable turnip, many smart guys (and girls!) out there would try to pluck her away if they could :-)
Now on to new business!
Mikawacchi is the best wingman ever! She knows.
What sort of monsters are Yamada's parents anyhow? NEVER letting her go see fireworks that her town is famous for? That's just cruel. Perhaps she means '...by herself' or maybe '...with her friends' or something, and the family went together? But it sure sounds like she'd never seen them up-close. (The entire town can see them I'm sure, but it's different when you're 2km away, eh?) Monsters!