On average, from what I've seen, takes from 8 - 9 weeks to flower.

So, based on this, give it 3 -4 more weeks and see how everything is looking. Of course, you situation may be different than the average so just watch the colors of the hairs and chop it when it's as done as you want it to be.

If you REALLY want to pump up the weight, try to feed the plant as much as it can take without showing any external damage (tip burn).

SMG