Dear Rishav,

Yes you are absolutely eligible to apply for JEE mains, the Board does not matter in your case only JEE advanced score will be applicable.

Its unfortunate to learn about your school, but go ahead and appear for your 12th boards from BBOSE because that will not be a hindrance and you will not have to drop a year.

I would also like to provide you with JEE eligibility criteria so that you don't have have complications. I am hoping that you might have filled the application form that was available till March 7th.

Since JEE Main 2019 is now being conducted by NTA- National Testing Agency that has changed from CBSE in past years it is important to know the eligibility criteria now more that ever, considering the shift. The eligibility only allows you to know whether you can appear for the entance exam or not and does not gurantee any kind of permission for admissions to the IITs, NITs, CFTIs which the JEE main offers. There will be two attempts one in january and one in April. 

Age Limit: There is no upper age limit for JEE main, however, the candidates need to complete their 12th standard or appearing.

Qualifying exam : Candidates appearing for 12th in 2019 or completed 12th in 2017 or 2018, to be eligible for JEE 2019.

Subjects/subject combination : Mandatory 5 subjects in class 12th or equivalent qualifying exams.

The 5 subjects for B.Tech/ B.E. are: 1-Language, 2-Physics, 3-Mathematics, 4-Any one of (Chemistry, Biology, Biotechnology, Technical Vocational Subject), 5-Any other subjects

The 5 subjects for B.Arch/ B.Planning are:1-Language, 2-Physics, 3-Mathematics (compulsory), 4-Any one of (Chemistry, Biology, Biotechnology, Technical Vocational Subject), 5-Any other subjects

Number of attempts: Candidates can appear for 3 consecutive years and are eligible for both the attempts in that particular year. However, that academic will be considered as one.

 For more information please visit: https://engineering.careers360.com/articles/jee-main-eligibility-criteria

I hope this solves your query. Feel free to ask more.

Best of luck for your examinations.

Cheers,

Arpita Goon.