Get checking them trichomes man , only way to tell , had some plants pistils turn colour weeks and weeks before trichome maturity , at least with super lemon haze.
In my experience so far , they go into flower , stretch , flower , stop putting on more flower , swell , then nothing happens for a while , then the fan leaves get eaten.....they stop growing a good while before they are mature imo , least with my Sativa hybrid experience so far.