Textbox1.TextChanged not working

The TextChange is not working.  Typing works but the counter(TextBox3) does not work.  When 31 characters is rached it does not become read only and the message box does not come up.

Protected Sub Textbox1_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
     TextBox3.Text = TextBox3.Text + 1
     If TextBox1.MaxLength > 30 Then
          MsgBox("Over Limit Stop Typing")
          TextBox1.ReadOnly = True
      End If
End Sub