Yeah, if they are showing pistils then it shouldn't be long at all before they start to flower.
All in all, you've got some nice healthy plants! The size looks good for 3 weeks (28 days is 4 but still not bad for their size) and the leaves are nice and green, and reaching up for the sky. I call it the "grower's salute", and it means your plants are liking what you're doing.