Its never too late to repot! The pots you are using do look a tad tight, are the tips of your leaves a yellow??? If they are a little yellow you know its time to repot. You are growing an Indica, and a fairly stout one at that so i would suggest you find a nice 11L pot, mix some perlite and dolomite lime in there if you havent already, and give her a nice watering. Yellowing leaves at the bottom of tall plants isnt a big deal, but yours isnt that tall, so i would try to give her a little more Nitrogen, and if that doesnt work then flush her, wait a day or two and give her some mild nutes with high P and K. Otherwise she looks decent, but like Weedhound said you will probably get a couple grams, i think (if she has 4 more weeks left to flower) that you should easily be able to get 10-12 grams. Should have vegged a little longer ;-)
Peace