I am a middle class student. I want to join in btech
You don't need to worry about the studies as the loan facilities are plenty for students with even decent academic background. As per eligibility there is no minimum pass percentage so you will be judged by Jee Main exam for admission in Btech course for engineering. There are other exams too like BITSAT, SRM, VIT etc.
Do you have any specific exam in mind for btech you want to know about.