i try to wait until i see a few golden trichomes but those certainly are looking good to go. cut a small bud, dry it and try it out.
what effects are you looking for? what strain is it and what are you going to use it for?
if it is a heavy indica you will be using for pain, sleep, wait until you get some golden tris.
if it has a lot of sativa, it is ready, cut it.