In general, whenever you want to start learning, you can start learning! Courses on Kiron Campus and Coursera are self-paced - you can start them any time you want. You usually have as much time as you need to complete these courses, and if you don't like the course, you can also start another one without finishing this one. This also means that there are no teachers, you are responsible for your own learning progress.
If you are part of a specific program at Kiron, you will always get updates per email about any live interactions.