had a small outdoor sativa given to me and need some info on flowering stages

My buddy gave me a small sativa 4 days ago that he didnt start until june 10th.its only about 3 ft. tall.it is a female but is in preflowering and the pistils are mostly about a centimeter long.the plant is in good shape but i am just wondering if it will flower completely by around mid october.he did not use any nutes on it at anytime,and the soil he used is not great either.im just curious.any help would be greatly appreciated.

Yeah. You should have a fully budded plant, ready to harvest, by mid october. You can even wait until late october to harvest. When 3/4 of the pistils have turned brown, you might wanna harvest, though i prefer 1/2 of the pistils being brown as it gives you more of a head high as opposed to a lethargic, lazy high.