No. The fourth week of, pills have no active ingredients in your birth control pill. They are there only to help you count the week until youmstartmthe next package.
Birth control pill. A week of placebo/inert pills.
Up to 1 month before. Generally, obs will tell you they want you to have a period off birth control before trying, to see if there are any problems with your period; that said, I have a 17 year old daughter who is living proof that waiting is not necessary. Good luck!