What was it doing the other few weeks if not vegging? I had to chop the tops off of three big plants on my first grow or I would have been harvesting buds in my attic - closet grow. I did pinch a few tips when they were young, before I had the closet set up. With mentoring from a generous, helpful member on here I still have a few jars of bud left, a year later. HST, LST, and a lot of twisty ties and yoyos were used. It'll delay your harvest but you'd yield a lot more if you ... chop off a good bit of the plant. Growers have their own methods, topping after nodes 4, 5 or 6 or just LST to spread out the plant. You can hard stress a plant, train a stem to grow at a 90 degree angle for a foot, sideways, the growing tip end will seek the light, sun above. You want an even canopy. Where you live is the amount of hours of daylight on the downswing? If so will you have enough daylight hours to complete the harvest?