Hello Mansi.

You scored good marks in 12 up board.

You can surely participate in JEE mains exam 2020. Not only you can participate but you can surely try and get good NIT. You are eligible for that as only 70 %are required for NITs.

To check eligibility criteria you can visit.

https://www.google.com/amp/s/engineering.careers360.com/articles/jee-main-eligibility-criteria/amp

Hello

Yes you can participate but if your PCM aggregate is not 75% then no, you won't be able to attend JoSSA counselling and won't be able to grt any govt college through JEE. You should give Improvement exam along with the JEE preparation so that next year when you give JEE and have a good score then you would be eligible for JoSSA counselling.

Hopr this helps