Hi Sameer,

Yes, why not!

As there is lockdown in the country, these are the 20 golden days you have, don't let them go in vain.  You can start your preparation as soon as you can as, AS SOON AS you start you will get more more time for preparation. You are in Class 11th, so it is the best time to start the preparation.

Coming to the second question than NO, coachings online or offline are not at all necessary for JEE Preparation. If you can study according to your planning and can study even if you are not willing to, then you can prepare well without coachings also. Coachings are only to keep you motivated and hard working, but if you do it yourself, there is no requirement.

Refer here for more detailed information about 'How to Crack JEE Main without Coaching?' - https://engineering.careers360.com/articles/how-crack-jee-main-without-coaching

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!