Are this good to start flushing?

You flush toilets, not plants.

can't see enough in pictures to tell you specifically... Also, this entails some personal preferences too... You want to test early-mid and late harvests to know what you prefer best. Use that scope on multiple buds -- calyx trichomes only.. ignore trichomes on the leaves. generally speaking, early window is 10-20% amber. That's an average... colas at top will be more mature than buds at the bottom. You have an option to stagger your harvest too. Cut top colas off when they look good, drop lights a bit and let rest of plant simmer for another 3-7 days or whatever... As long as it isn't 2 or more weeks, you won't see any nanners from this stress as they won't have time to grow. Other cues show a plant near end... all your pistils have color and starting to retract... This really does come down to personal preference... you'll have to feel your way through first couple harvests, and then it'll be more second nature with a bit more familiarity and knowledge of what you like best from your buzz. More amber generally means more couchlock type of buzz.. probably better for a sleep aid too.