My mother learned to sew on a treadle at age 5 (and got sent home from school for "lying" when she said she made the dress she was wearing); she taught me at age 7 with doll clothes; my daughter made a jumper at 5 1/2.
Do you have a sturdy stepstool, like your daughter may have used to reach the sink? Put the foot pedal on that so she can reach it!