By default, Canvas places all grades/assignments without a due date in the last grading period of your gradebook. Therefore, before the end of a quarter, you will likely need to assign a due date in order for her quarter to calculate correctly.
Some examples of why you might do so include:
You provide feedback to students that does not require a homework assignment. For example, a participation grade.
You want to include a summative assessment grade that does not require a homework assignment.
Some practices to consider:
Using a Saturday or Sunday to assign a due date for a grade.
Watch How to Ensuring all of your Assignments have a Due Date to ensure the grades are located in the correct grading period