You should be keeping a log book to track your performance. It may not seem important, especially at the beginning, but you will likely regret it later on. CrossFit uses a black-box methodology: stuff goes into the box, something happens, and the result comes out. If you don’t know what you put in to the box, it’s much harder to gauge and interpret the results. One of the fundamental aspects of CrossFit is that our results are measurable, observable, and repeatable. We do benchmark workouts so that you can repeat a workout a month or two later and see empirical results and specific progress. By writing down every workout, you will have a great record of your progress, especially if you are scaling workouts. You will also have a better idea of what weights or progressions to use when doing similar workouts, such as a one-rep max. A couple months from now, you can look back fondly and compare what you were doing when you first started to what you are capable of now. That’s how we measure results. You’ll never forget the feeling of getting your first kipping pull-up or doing a benchmark workout as prescribed, but it’s great to be able to look back and see what you did to get to that point. Write it down.

Check out this article by Jon from Again Faster for more details:

http://www.againfaster.com/articles/tracking-school.html

Also, the website www.logsitall.com has all the CrossFit benchmark workouts, weightlifting exercises, and the main site WODs. You can put in your scores and, if you choose, make your logbook public to compare your standings with other CrossFitters around the world.