depending on the size of ur light u could flower now or u could let it veg, if ur runnin one plant under a 400hps or mh then ya let it veg transplant it to a bigger container and top it or train it so u have more top colas, if ur runnin like a 250 or 150 hps or mh id transplant plant it when she needs it then flower her, if ur runnin flueroscents tubes or cfls id flower it now, maybe put it in a bigger container still if she is getting good root mass in the container she is in, if ur flowering with fluero's then ul wanna keep ur light closer than u would with a h.i.d. i know theyre sum great groups on RIU with growers than only use flueroscents and nothing else