The pic sucks but the bud looks ready or close by development. If going by eye when the majority of "hairs" have died back and are red or brown or whatever. Scopes are best and cheap. $15 for the 40X or $3.25 for an unlighted folding jewelers loupe on Amazon.
You have to get a scope and look at the trichomes for sure. you need at least 10% amber or more. more the better. Unless you have been growing long enough to see the ripeness with the amber affect on the bud and leaves. every strain acts different. also the uper cola's that get more sun ripen faster than the lower. I take some tops when their ready which allows the lower ones to get more sun and ripen.