how do I know when I should harvest this?

Cut back Nitrogen and increase potassium and phosphorus. Check with a jeweler's loupe or 40-60x magnification and look at the trichomes

Hey hey ! Your plant are not ready at all my friend, it is not taking too long, flower stage announced by breeders is under best conditions : optimized feeding, good lights, top climate and co2. You must focus on your plant and and take your time ! There’s some good advices into your comments !

2~3 weeks I guess. And you shouldn't put blind faith in breeders' indications as to how long a plant will last, especially with "autos", unless you know how to give your plants the best conditions.

How long more? because i didnt feed it right did it slow her down? it was supposed to be an 8 week grow its going on 11 now

Forget the pistils. The change from white to amber only indicates that your plant is entering the last phase of flowering, when the flowers become large buds. It's certainly not a sign of when it's time to harvest, unless perhaps they're all amber. Only the trichomes are important. And you're a long way from harvesting yet: your flowers have just started to fatten and already your plant is showing signs of a potassium deficiency, which is essential at this stage, given that you've just stopped feeding your plant. By the way, your fertiliser programme has been a bit of a mess from the start. It's good that you ended up choosing a real fertiliser programme instead of giving your plant random stuff with an NPK ration of 15-30-15 (instead of 20-10-20), but it will have taken you far too long. ><'

Compra una lente di ingrandimento e guarda i trichome da vicino, se vuoi un effetto pesante da couch aspetta finché i trichome non saranno per la maggior parte color ambra, se vuoi un effetto meno fisico raccogli quando i trichome saranno opachi. Peace

btw I'm aware she had a calcium deficiency it was to late and even though it was fixed it was still affecting her, maybe thats why its taking so long?