Hello @Michael Saia,
João Marques is right. but overall there are 2 issues so I want to elaborate to make sure we get this right:
1. In your dateselector - dateselectorOnSelect handler, you must assign the 'StartDate' and 'EndDate' so that the dates selected by user in the Date Picker are assigned to the widget correctly.
2. Then in the dateselectorOnSelect logic's assignment, the assignment should be the other way around, as shown below, so that the selected dates from the datepicker are now assigned to the local variables used by the aggregate:

This should do it,
Regards,
AJ