Hi Sarthak,

Don't lose your hope ...Not only have to pass ,but you have to score more than 75% in your board exam .

Then only you are eligible to make your dreams come true.

If after compartment You have passed the exam In year 2018 Then you are eligible to appear in  JEE Main. As mentioned in The JEE Main Website as follows

Only those candidates who have passed their Class 12th Examination or any equivalent qualifying examination in 2017 or 2018; or those who are appearing in their Class 12th Examination or any equivalent qualifying examination in 2019 are eligible to appear in both January, 2019 and April, 2019 JEE (Main)-2019 Examination.