I would say take it seriously but do not spend all your time only studying. Do other things as well. Make friends, go out, participate in CCA, see the world, take internships or externships. Go and get work attachments. Go and get a more rounded experience. You may miss an A and get a B+, or miss a B+ and get a B, but never mind. You don’t have to have a perfect score. In life, nobody remembers whether you get a perfect score or not. And the person who got the perfect score doesn’t always do the best in life.