It is not at all a big deal to score 8.5 in the first year. Just focus during lecture hours and then just give a reading once in a while and dive into the books a little time before the exams especially during Midterms and End Semesters. This will fetch you great marks.
Also do take quizzes and sessionals seriously as they often become grade changes in many cases. Try to aim for 75 marks in each subject. Even if you fail, if you try you’ll end up getting 60+ in each subject and that is enough for getting 8.5 CGPA in the first year.