No! You cannot fill the form now.The official authorities allowed candidates to fill the JEE Main application forms till 1st January 2023 and submit their fees till 2nd January 2018.Now, as the last date is over, you wonu2019t be allowed to fill the form. As you would not like to waster your whole year, you must try other Engineering Exams such as BITSAT, VITEE etc.Go for it! Good Luck!