I was kind of planning on letting her go for 8-10 weeks in veg to let my background girls grow up a little.
Edit: I'm not topping, nor have I
Most people top indoor to fill a tent. It can increase your yield. 8-10 weeks is fine. Just make sure you have the headspace because it'll stretch. Some as much as 100%. I have one that stretches 2-300%, but it's an outdoor girl so it doesn't matter much.
It's knuckled at the split, so that tells me that something happened. A knuckle happens when the plant needs to heal an injury. You see it often with branches that are supercropped, and in cases where the stalked was cracked. I suspect your young stalk was cracked enough to have the plant shoot another branch, and the damage healed over. It doesn't happen often like that, but you'd be surprised what a weed plant will do to ensure it's survival. But the stalk was definitely damaged at one point.
Your colas will be a little shorter, but you'll have two.