If you are on the fence about whether or not you are a Satanist after having read The Satanic Bible, you are probably not one.
You don't "convert" in the same way as you would to any other religion. You realize that you are a Satanist, and recognize it for yourself.
That said, welcome.
Hope you learn what you want to know about the religion, and can at least appreciate certain aspects of it, regardless of whether or not you are a Satanist yourself.