What happens if I repeat this class?

I'm in my last year of middle school and I'm taking mostly high school courses. However, I suck at Algebra. We're having a baseline test that if we don't pass with at least a 70% we have to repeat the class in high school. Honestly, I don't understand the subject all that much so if I have to repeat it in high school I don't mind much since it's a high school class anyways, The point is, I wanted to know what effects this could have. For example, would it affect my chances at getting into a better college? Please help, this is really stressing me out...