Should I retake the ACT?

<p>So I took the ACT last year and got a 31. I just took it for giggles really. I knew absolutely nothing about the test, did no studying, and just rolled out of bed and took it. Now I know with a brush up on math and some studying I can get a higher score. My dream school is USC and because of the number of units I have they will look at my scores. Should I just leave my 31 or should I retake it for a higher score? If I do retake it will it have as much weight as my first score?</p>