First of all, congratulations on your baby girl
You will be able to follow CD, but not until she is 12wks old......
Now, dont be disheartened... its just three short weeks. Use this time as preparation - start to increase your fluid intake and begin to cut out the usual sugary carbs (you know, all the ones we really don't want to go without
)
Preparing your body in this way, and choosing good healthy food most of the time will help to ease you into Sole Source (or whichever plan you and your CDC discuss is best for you)
Congratulations again, and good luck for when you start!