Please remember, when you start learning a new concept, it's perfectly okay to go slow. There's absolutely no point rushing - the important point is to grasp the concept and to use it for solving problems. So take your time and go thru every lesson. Some of the topics you might already know and it's perfectly alright to skip them. However, we encourage that you watch the videos as a review session. Often times your teacher will show you some tricks and also will talk about where and how a concept is used in real life.