Maybe something like this ?
Code:
Private Sub Worksheet_Change(ByVal Target As Range)
'limit target to a single cell at a time
If Target.Count > 1 Then Exit Sub
'limit to specific column
If Target.Column = 27 Then
'don't do anything unless target contains something
If Target.Value <> "" Then
'prevent changes made by this sub from triggering itself
Application.EnableEvents = False
'insert below row of target
Target.Offset(1).Resize(1, 12).Insert (xlShiftDown)
're-enable events
Application.EnableEvents = True
End If
End If
End Sub