My high-functioning son is 10 and and I would like your daughter to know it can get better. Keeping calm is a skill you can develop with time and patience.
Being outside away from people and in nature seems to help calm my son quite a bit. He is learning to be less triggered but sometimes he just needs time away until he can collect himself. Pets and stuffed animals seem to help him, too.
Pen and paper pad? Look serious like you are taking notes but you are doodling dinosaur battles.
Can confirm that it does not taste good!