Stressed out about the asvab, need answers from people who have struggled as well.?

The branch of military I want to serve is the coast guard. friends and family have told me that the asvab is a piece of cake. I have the asvab study guide. I meet the standards in Paragraph comprehension, word knowledge and general science, and Im approving my weakness, math. I know a little mechanical composition, but the rest Im blind. how does it score? I would like to do Marine biology, or something exciting like search and rescue, what does my score need to be?