Grandparents expect her at every evening pooja, and half-yearlies start the same week

My parents do a full Ganesh setup at home every year, a few days of pooja with family coming in the evenings. My daughter is 15 and has always loved it. This year her half-yearly exams start the same week. My mother has already said she expects her there every evening. My daughter wants to go but is also panicking about chemistry. I'm the one in the middle. Do I tell my mother she'll come only on the first and last evening, or let my daughter decide and deal with whatever she picks?