Just ask? Isn't her older sister in the next group? And she's at the top of the age range, so it might not be as big of an ask as it may feel. Lots of parents want both kids together in these kinds of orientation activities, and it's also not that unusual for younger siblings to be a little precocious socially and emotionally, compared to same-age firstborns. I don't think you even need to get into her grade placement, actually.
ITA with aeh.
I'd also say that how far I'd go to advocate re this depends on the length of the camp - is it just one week or multiple weeks? If it's just one week I wouldn't stress over it if dd had to attend with the lower age group and put up with a silly out-of-date book. I would save my advocating bank account for times when my child might be attending a camp that's studying a subject where they really need to be with the correct intellectual placement; this type of camp I might consider it's a one-time thing (I'm guessing it's a one-time orientation) and let it go. On the other hand, if the orientation is for the school year and based on grade she'll be in, I'd be sure she was placed with the correct group for her grade.
Best wishes,
polarbear
