Help with debugging a VBA code

[soniajaswal]

Hello, I am new to VBA programming in excel. Can you'll help me with debugging the following code, i get an error '13' while executing.

Private Sub CheckBox1_Click()
If CheckBox1.Value = True Then Range("K5").Value = "We are good"
If CheckBox1.Value = False Then Range("K5").Value = "Follow up"
End Sub

Private Sub CommandButton1_Click()
Dim fdate As Date
Dim sdate As Date
Dim n As Integer
fdate = DateValue(startDate)
sdate = DateValue(sendDate)
n = DateDiff("d", fdate, sdate)
MsgBox n
End Sub


Private Sub TextBox1_Change()
Dim startDate As String
startDate = Worksheets("Sheet1").TextBox1.Value


End Sub

Private Sub TextBox2_Change()
Dim endDate As String
endDate = Worksheets("Sheet1").TextBox2.Value
End Sub