Got an email this morning from another parent in the class.

DD is in a split 4/5 gifted class. She is in 4 but can log on and do her CTY math online during math class, so she ahead.

One of the girls in grade 5 struggles with math. Apparently she asked DD to help her since she has to redo the test (like no child left behind, they can redo is the score is bad). The email asked if DD could provide peer tutoring to her child.
One, I feel this is a huge responsibility for a 9 yo. And DD is short on time.
I responded, allowing for one time, that I would be there and could assist in the tutoring since I felt that helping a child that struggles more in math to have a different tangent in presentation. Since I did some of that when I was in college and teaching high school student that struggled in math.
After I sent the email offering one day next week, the only day DD had available, I felt a little off put.
Advice?