It is always good to have knowledge in your brain. Who knows, when you might need it.

Also, in gate preparation, it forms an important section of questions. As it will be used in Taylor series, Maclaurin series, Differential Equations, Gauss Divergence theorem, Stoke's Law and much more.

So, I would suggest you study hard and believe in yourself because they are not that much difficult until you make a different image in your mind.

 Overall, You are going to use them a lot in your first year and maybe later. But they are quite useful in GATE preparation.

Not that much  . However they are basic to engineering . You will have a better understanding if you are thorough with their concepts .