One thing I often hear when I tell people to try CrossFit is "I need to get in shape before I can do CrossFit". That doesn't make sense! CrossFit is all about improving yourself- scaling to your level, then next time around beating yourself!
We often get caught up in the competitive part and forget that we are all here for our own personal reasons. Your goal could be weight loss, more confidence, health, the ability to lift ridiculously heavy weights... CrossFit is NOT about the competitions, it is about YOU competing with yourself to be better than you've ever been. You will not be judged if you can't squat clean 300lbs; you are no less of an athlete if you are scaling the workouts. If you want to be great, be better than you were yesterday, not better than the person next to you. Keep working hard and pushing yourself and you will see results, you will improve!