You see, to a person who needs predictability and has sensory sensitivities to sounds, as many autistic people do, fireworks are pretty much the ultimate worst nightmare. That's certainly what they've been for Caley - the bursts of sound are out of her control, inescapable (even with her earplugs and music), and come at random intervals.
As she says, "Fireworks are evil, they're evil, they're evil! And while they may be pretty, I can't really enjoy them. It's too boom-y."
As you can tell from her phrasing, the fireworks have made her pretty disregulated. I see those signs that veterans put out front saying "Veteran lives here, please be kind with fireworks" and wish they made an autism version...
In the meanwhile, all I can do is cuddle my sister and teach all of you why the 4th of July celebration may be less than celebratory for people on the spectrum. I hope this helped you understand a little better.
[Note: Like with all the posts here on ASE, Caley approved what I wrote before I published it.]