Limit Scroll Area - Code Activates Only On Mouse Or Keyboard Input

I have a worksheet that serves as a navigation page for the workbook and use the following code to restrict from scrolling off the viewable content. The problem is that the code doesn't kick in until either a click if the mouse or keyboard input. This initially leaves the worksheet open for scrolling until input is received.

How do I make this code activate when the wb is loaded? Code in the Thisworkbook module already makes the menu the visible sheet, and code limiting the scroll area is in the sheet module.

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
With ActiveSheet
.ScrollArea = "A1:L11"
End With
Range("A1").Activate
End Sub

I've also tried using "Range("A1").Select", but it doesn't work either. How can I get this to work correctly?