_NB_ it could utterly shape the next 5-10 years of your life and in doing so drastically alter the path of of your life 70 years from now.
(Depending on the exam, but if the exam defines college entry it is not an unreasonable statement. Of course the trick is to realise that success doesn't mean a better life, and failure doesn't mean a worse one. It's like Rimmer getting held down a year at school and becoming Ace instead...)
"Relax. Don't worry. Outcome of this paper will not matter at all 20--30 years from now. Impress me with your knowledge."