The React Nanodegree program is composed of one (1) Term of four (4) months. A Term has fixed start and end dates.
At the bottom of your classroom, you should see a date that tells you when your term ends. That is the final date by which you must submit a passing version of every required project if you wish to graduate. After that date, you can no longer submit any projects or get help from mentors. If you are a student on a term-based model, you may qualify for an extension to this date if needed.