I grew Blueberry once, which is supposed to have a fruity smell, like, uh, blueberries LOL but my plant didn't start smelling like that until they were 6 weeks into an 8 week flower cycle. Even then, the buds didn't start smelling really good until after I had cured them for a couple of weeks after harvest.

Smell doesn't really have a direct correlation to potency though. It's obviously the trichomes that are full of THC that produce the high. So my question is, why are you concerned that they don't smell? As long as they're forming crystals on the buds and leaves, isn't is all good in the hood?!