If you flower too early it can be stressful.
Remember that the seed in nature sprouts in spring, and gets a summer of long days before the onset of fall, and the shortening of the light hours, trigger its flowering response.
It is best to allow a plant to at least reach sexual maturity before it is flowered. The vast majority of strains will show this in the form of nodes that begin to alternate, rather than having a pair of leaves come off the same spot on the stem.