Let it grow to node 5 , then consider topping , your jumping the gun my man .....
It does not look like node 5 ....
and yes right on th "V" , remember , cut the stem , not the growth .."to achieve a topp"
You see the new leaf's about to open in your pic , i would top as soon as the NEXT new leaves have opened up , patience will reward you ..... is it a cutting ?
Also that's quite a large pot/growbag your using , the plant will benefit by letting the roots spread out first.....
no grew it from Seed Its Kings kush 19 days old, just transplanted yesterday and now that i think about it ur right i should give it time to adjust to its new home. (5gal smart pot)
Had some issues with bad soil thats why the 2 bottom leaves are yellow but its all good now
As you have just re-potted , it may stall for a couple of days to a week , you will soon know when it has kicked back into full growth , it wont take long and will be ready to top , like in the vid..