Yes, you can reset your progress (or restart the program) at any time and redo all modules. Please note all your stats will be lost, and you'll start from module 1 while all other lessons will be locked. However, the bonus exercises from the Exercises section will still be available.
To start over, please go to the Lessons section and scroll to the bottom. Next, click the REVISIT CORE MODULES button and then Restart. (see screenshots below).