JEE Main

Hi,
As you have not appeared in JEE Mains exam, you cannot get admission in any government college. I will suggest you to go for Lovely Professional University and appear for LPU-NEST exam. You will easily get a seat in B.Tech there. If you perform well in the LPU entrance, then you will get scholarship also.

Yes, you can take admission for BCA on the basis of your 12th grade. JEE Mains exam is not required for BCA.
There are many universities that offer BCA like Amity University, JIMS University and many more.

You can refer the link mentioned here:
https://www.shiksha.com/university/gjust-guru-jambheshwar-university-of-science-and-technology-hisar-3273

Refer the following link:
https://www-shiksha-com.cdn.ampproject.org/v/s/www.shiksha.com/engineering/articles/amp/how-to-calculate-jee-main-percentile-score-know-normalization-process-blogId-19933?amp_js_v=a2&_gsa=1&usqp=mq331AQCCAE=#referrer=https://www.google.com&_tf=From

NTA has announced results for the exam of JEE Mains that they conducted just now. They have not declared any cutoff. I feel the cutoffs will be declared only after second set of exams are over. Since cutoffs are same for both the sets exams. I suggest you see the announcement of the same by NTA in April.

Yes, you can get admission in UPES for petroleum engineering.

Please say your category for better guidance otherwise it is impossible to say about it. You can have an idea by trying Shiksha's college predictor.

Your percentage is not good enough to get the best colleges. Just go through the link that is mentioned here:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

Verify the link:
https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor

https://www.shiksha.com/b-tech/resources/jee-mains-college-predictor
Go through the above mentioned link with your percentage.