Need some advice please and thank you.

This is my 3rd op inside. I'm using cfl, 1 200w with reflector and 2 23 watt for full spectrum. From seed, September 7th she popped out the ground. Just put her in 5 a gallon final pot, about week and few days ago. Also started LST. Happy with results so far, but my problem in the past, was to small of containers in flowering stage. I don't wanna screw this one up, but never LST before.... from soil to first topping is 6 inches then about 7 inches from there to the tip of the biggest branch which means she would be 13 inches just over a foot tall. which brings me to the question when should I flower?

General guideline is when your plant is 1/3-1/2 the final size you want/need. How much height do you have? You have said nothing about the size of your grow space and this is very relevant to the question you're asking.......

Cheers!

I've grown 4ft monsters in 5 gal pots topped and trained flowered at 16 inches

5.5 feet but have a inline fan and filter on inside. With grow light and fan and filter and bucket I have roughly 3 feet of grow space for the girl. But my baby is only 6.5 inches tall. The height of 13 inches I gave in my original thread is from bottom to end of trained main stem. I've been told my flowers have been smaller cause I don't give them a bigger pot for flowering. Biggest pot I've used. 16 inches from bottom to end of main trained stem? And ended with a 4ft from bottom to trained stem?

I'd Let her get 10-12 inches.