We're in the process of sending in the paperwork for my next child. They have had his first SAT score for six months. It's nice if you can get the actual registration earlier than this. But a lot of schools won't do it until now anyway.
Shortly after you send it in you should receive notification that it has been received, though it will take some time before it goes through the system. Many of the notices of preliminary status should be going out about now. You won't get your final status until after graduation and your HS sends in your final transcript.