I was studying calculus today and decided... Answered

What you might actually need depends on what you might be doing. In my work (experimental particle physics), for example, I use both integral and differential calculus on a daily basis, along with complex analysis, and four-dimensional relativistic kinematics. If you major in engineering, you'll certainly be using the calculus and vector algebra. If you're just doing accounting, clerical work, or flipping burgers, you won't need any of that stuff.

Any ideas for how i can take my knowledge from school last year and remember it for this upcoming year?

Use it. There is no better way to make sure knowledge stays with you than contextualising it in a problem and having to use it. Find calculus problems, or if you can't, make some up.

I'm sure you are familiar with the usual sort of questions you are posed, look at advanced exam papers etc. to find more taxing ones. I distinctly remember thinking I knew all there was to know about quadratic equations, then being asked to derive the quadratic formula (you know the one, -b +/- square root b² - 4ac etc) from ax² + bx + c = 0. That bent my brain a little :)

I would study optimization problems using differential calculus. I used them in my planting Instructable to figure out how to maximize my plot area, while reducing the cost.