Selection Change Event w/Drop Down Selection

I am running the following selection change event however it only works AFTER I select a different cell and then re-select the target cell. The target cell had a drop down list for the user to select either dayshift or nightshift. I tried to have it programmatically select a different cell before re-selecting the target however that ended up in an endless loop or sorts. Any ideas on how to get this to work immediately after the user make a selection?

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Not Intersect(Target, Target.Worksheet.Range("N4")) Is Nothing Then


If Range("N4").Value = "Dayshift" Then
If Range("N13").Value > 0 Then
Range("AA2").Value = "05:00"
Else
End If
If Range("N14").Value > 0 Then
Range("AA11").Value = "05:00"
Else
End If
If Range("N15").Value > 0 Then
Range("AA19").Value = "05:00"
Else
End If
End If
If Range("N4").Value = "Nightshift" Then
If Range("N13").Value > 0 Then
Range("AA2").Value = "17:00"
Else
End If
If Range("N14").Value > 0 Then
Range("AA11").Value = "17:00"
Else
End If
If Range("N15").Value > 0 Then
Range("AA19").Value = "17:00"
Else
End If
End If
End If


End Sub

Unfortunately, I can use the worksheet change/calculate events because there will be other instances of these cells being zero throughout the day. It can only happen immediately after the user chooses either dayshift or nightshift.

Just found out if I changed this from a worksheet_selection change to worksheet_change event it works perfectly! If only everything in life was so easy. Thank you for the suggestions though. Appreciate it.