Wow beautiful! They're at 12 weeks, I'd say they look more than ready to get a couple strong waterings of plain ph'd water to flush out any of that big bloom and tiger and calmag and you're ready to chop. Even with the few white pistils still it's ok...they don't always all change colors and sometimes you don't want them to. There's a fine line between ready and past the optimum harvest time.
Happy trimming. ✌️