I personally wouldn't do it unless what you upload as the course (first 6 chapters) makes the complete course and everything you upload beyond that is bonus content. People usually want a complete course when they take it, one that delivers entirely on the objectives laid out upfront, if it doesn't do this because the content hasn't been added yet then you are likely to get low ratings. There is no hurry, it is better to make sure you have a complete course before going live, not a partial course. If each part works as a self contained course you could create multiple courses and state with each course what skills and knowledge the student needs before taking that course, understanding it can't be that they need to have taken your specific prior course, but they should have certain knowledge and skills from wherever they learned it.
All the best
Dan
