Need magnification to see trichomes. A cellphone camera zoom isn't enough.
It's a total guess, otherwise.. when it looks ripe, if new to growing, then i'd suggest you want another 7 days.
order a $5 monocle and start observing trichomes
https://duckduckgo.com/?q=trichome+harvest+marijuana&t=ffab&ia=web
take your pick on the suggestiosn, as none are thoroughly proven to any extent... trial an error after this point will get you where you prefer things to be in future.