Hello Vale,
Nice grow so far! things are looking good. As far as having good nug to smoke, you shouldn't worry at all. I have hear of people harvesting the tops and then waiting on the rest... I don't do this because when it's time to chop we can't be bothered to wait. Also, harvesting a plant that has slightly different development in the buds will yield varying highs, which is often a good thing when you are preparing to smoke a lot of the same type of smoke for a while.
Just my thoughts... Again nice grow!
-greatherb