The correct response is:
Yes, but this is a very usual arrangement for those who work on commission.
In many states, it is legal for employees to work on a commission basis, even if their base pay is minimum wage, as long as they comply with labor laws regarding minimum wage and overtime. Commission structures are common in sales positions, and it is typical for earnings to fluctuate based on performance and sales cycles. However, it's important that her total earnings meet or exceed the minimum wage for all hours worked.