When Should I Flower?

Hey all, this is my very first grow. Only growing one plant for now so i can learn the practice well. I have a clone off of a mother Kush plant and it was about 7 or 8 inches by the time i got it (came in a party cup with small amount of soil for it to root). I transfered it to a 2 gallon pot and i've had it under a 400w light on a 17-7 schedule for veg. It's been 5 weeks since i got it, but the plant is only about 18 inches. Been using root booster which contains an acceptable amount of nutes and i use this every other water (watering ever 3 days or so give or take how the soil feels). I was thinking about 2 more weeks then flower? Just wanted some input from experienced growers. And how long should i flower it before harvest? Any other tips i should know feel free to include, thanks for reading ill post pics, and please post if you have any answers

very nice plant. 18 inches? id flower now. i think og kush 8 weeks flower time.

Anyone else??

Depends on how big you want'em? How much head room you have? It's going to gain almost 2.5x to 3x in height! You at 18" it going to be 45"- 54" est !