Have you ever faced a difficult subject? No need to worry. It is common. The first step is to have a good attitude. If your head is filled with negative thoughts, it will probably affect your ability to perform academically. Once this is sorted, you can take on new ideas and concepts.
Think of challenging subjects as going on vacation to an unknown country. First, it will seem somewhat chaotic and disorganized. This will soon change. With the use of a map, you will easily figure out where to go. Soon, you will manage to navigate without using a map. On top of this, you will feel comfortable and safe in your new surroundings.