Well that depends on the score you obtain in your jee mains as well as on you jee advance scores if you wish to pursue engineering from IITs or nits. As per the new policy of jee,the 40% weightage of the 12 th scores is not taken into account anymore.
Also there are state level engineering exams like UPTU etc that offer fee waiver based on your boards percentage. Admission in these colleges completely depends on the score earned in the entrance exam.
However,there are certain good private engineering colleges that might consider your boards score.