You have missed your three exams in 1st semester, but don't get confused, because you will be promoted to 2nd year and you can write and clear all these backlogs of 1st semester. So, you will fill carry over form for 1st semester's backlogs in 3rd semester and give exams with your juniors.
Universities gives 3 more years in addition to 4 years ofcourse duration . So in total you will have to complete your degree course in 7 years. If you will not complete your course and all backlogs in this time period, university will issue NFTE i.e. Not Fit for Technical Education) certificate, after that you will not able to take admission in any other professional course in any university.
Similarly, AKTU will also give additional time period of 3 years for clearing of backlogs and completion of course. But try to complete all papers before 8 semester of 4th year. So that you will be able to appear in GATE exam also. You will be able to appear in the campus selection process and any good company may hire you.
Now focus on your study and make proper study planning and do work hard. You will definitely get succeed.