Hello Parth 

Eligibility criteria for BITSAT is :

Age: There is no age limt for exam.

Qualifying Exam: Candidates need to have passed their 10+2 or equivalent exam from a recognized Central or State board or its equivalent with Physics, Chemistry, and Mathematics as subjects and adequate proficiency in English.

Minimum Marks in Qualifying Exam:Candidates must have secured minimum 75% marks in aggregate in Physics, Chemistry and Mathematics/ Biology in their qualifying exam or equivalent. They also need to have minimum 60% marks in each of Physics, Chemistry, and Mathematics/ Biology subjects in the qualifying exam.

And students who give 12 th boards in 2017 are also not eligible.

So according to this you are not eligible to give entrance exam.

Hope you understand it.