i know im not leet at this or anything but remember when overgrow was runnign ALOT of ppl recommended or practiced a set day of 70 days for there sativa. so look to around day 60 - 75 of flowering.

also i would suggest cuting the timmer down to 8/16 and the last 2 weeks go completley dark or just keep it at 8/16. this might help kick her into flowering faster.

hope this helps