Hi there Majida! Hope you're doing all well.

You can absolutely attempt JEE Mains exams next year and join another college if you fair well next year, the only condition being you cannot attempt JEE Mains more than 3 times all over.

Hope this helps. Thankyou.

Hello aspirant , ye you are eligible to appear for JEE Mains . It does not matter whether you have joined an institute or not. Te criterias for JEE Mains is -: 

1) Candidate should have passed class 12 

2) Students appearing for 12th boards in 2020 are also eligible.

3) A candidate is having 3 attempts , in one academic session there are 2 exams,  but one academic session is considered as one attempt. Basically a student can appear for 3 years. 

Hope it helps..

All the best..