topping sativa plants?

I have a very nice looking sativa (long skinny fingers) and it is getting very tall it is now 18" decent internode distance the nodes are not alternating yet I usually wait a couple of weeks after this happens but with the speed this plant is growing it may get too big... I have plenty of headroom but most other plants i grow average 3 feet and if this one ends up being 5+ feet tall I will have to raise the lights far above the smaller plants. So my question is topping a sativa a good idea? bad idea? no real difference? I top most of my plants just never had 1 that looked like this or grew this fast.

I'll tell ya why, its because your light is to far away, and its causing the plant to STRETCH get a flor. tube light, 1200 lumens, it produces a blue spectrum and here is the key to bushy plants. KEEP IT 2 INCHES FROM THE PLANT AT ALL TIMES. make sure you only do that with flor tubes. because any other lights are to hot and will burn your plant.

look at my setup of my skunk...

https://www.rollitup.org/indoor-growing/24145-super-skunk.html

HOPE I HELPED A LIL/ GOOD LUCK MAN!!!