hey there!

As far as JEE mains is concerned you can appear in the examination for the three consecutive years after you have completed your class 12th, that means you'll be eligible to appear for it next year too. And if you are persistent in your decision of dropping a year again then it is not much of a problem but you do have to give it all this year as it will be your last chance for the mains. And you can also apply for some other colleges for graduation if you want to explore some options beyond engineering.

You can also use careers360.com course for preparation of JEE. Here's the link - https://learn.careers360.com/engineering/jee-main/