I was a junior in my first physics course in high school, and did not have calculus until my senior year, where I had a second chem/physics course. In one case in the physics course in my junior year, I remember solving the minimum of a parabolic function by simply using algebraic techniques, where calculus would have offered a solution by setting the derivative of the function equal to zero. If Physics C is the first physics course, calculus can be helpful but isn't necessary. If "C" stands for physics course 3, by then, calculus is very beneficial, but I'd be surprised if a high school has already given you two physics classes by your junior year.
Physics C is a calculus based physics course so you would be in a disadvantage, but you could use sources such as khan academy or other websites or books to learn calculus. I highly recommend reading the book- No bullshit guide to math and physics by Ivan Savov, this book goes over the essentials of calculus and goes over it with physics examples.