Dont prune. There is no need at all, and it'll stress the plant, causing a stunt in growth, which you dont want.

If your growing it outside you need to wait untill the natrual light cycle is 12/12 for it to flower. The plant mesures the uninteruppted dark cycle which releases a flowering hormone.

You need to keep the plant in 12 hour direct sunlight and 12 complete darkness for 8 -12 weeks, if its a pure sativa it can take up to 14 weeks to finish flowering.

I suggest you read the grow FAQs and check out the growing forums, but at the moment it looks alrgiht.

[Remember you only want the female cannabis plant, not the male as the female is the only one to produce bud. A male plant will produce pollen which will not get you stoned.

Males plants have small balls and the internodes, while females have little white hairs all over the internodes.