Everybody Starts somewhere. The nice thing about Crossfit is that all of the workouts are scalable so if you can't do a workout as listed, you can do something more reasonable. (But still try to push yourself! You'd be surprised!
Because you've already done a week of the intro, you should know what you can take and what you can't.
But remember that nobody will judge you for having to scale down a workout or substituting anything, they started there too!