i let her veg for a month to the day, then flowered her!
You seem to have an unsually tall computer, so i'm assuming you bought it for that reason. Depending on the strain, you could veg for 1 or 2 months, but she'll probably double durring flowering if she's like mmine. I'm not extremely experienced with topping, but you should get a few nodes going on. Especially since most people clear out their lower brances for air flow.
good luck!