Don't top her at all. The idea is to grow bud stalks. Topping will give you a Y on the top. Little more.
Instead remove the large leaves shading the new stalks growing from nodes bellow them as shown in red.
The plant will slow down a bit but all of the lower nodes will produce stalks.
In a week you will have to remove the top new shade leaves as the plant grows them back every couple of days. Instead of a very tall plant it will produce more stalks a little shorter. Each stalk will produce a top cola bud. The best of the best.
In 30 days you will have a great plant not real tall but it will have 20 nice bud stalks.
You won't believe this plant when it's all sugared up in the fall if you do this now.
She is a little light green give her some tomato fertilizer something with a 12 first number.
get her growing. I know full well I'm asking you to trust me bud. Trust me and do this.