Private sub MyFilter()
Dim strFilter as string
strfilter = "SomeField = " & SomeValue
me.filterOn = not Me.MyCheckBox ' or me.filterOn = Me.MyCheckBox depending on how you want to filter
end sub
Then just call it in form load and the after update of the checkbox.
The bigger problem will be the fiscal year dates year after year which OP will have to eventually address.
What are you going to do when you hit the next fiscal year? If you are hard coding the filter you'll have to change it each year.
It would seem to me that all you want to do is toggle the filter on or off.
In the attached I have a field in the forms record source which is the fiscal year for the date field.
A combo box has a row source of all the distinct FY's.
The check box toggles the filter on or off.