Well it depends how you want your high to be. That will be more of a head high because there are more milky than amber, but you could chop her now if you wanted that. If not, wait till they go 50/50 for an all round high. For a stoned couch lock high, wait till they are all amber . I reckon you could chop now, if that's what you want from them
I'm no expert but from my experience if you harvest too early the high will be racey. But the high will not last as long than if you wait until about half cloudy/half amber. Since the high is more influenced by the type of strain, whether it be indica or sativa, the 50/50 trichome cut from a more sativa dominant plant will be more of an upper than a downer.
Yo gotta take into account of the whole plant. Look at the leaves if they are really yellowing, look at the calyxes see if they are almost bursting, the hairs should be receding. The plant should have a amber look to it. Etc... Grow it till its RIPE. If you want an indica, get indica seeds and grow it RIPE if you want a sativa, get a sativa strain and grow it till its, you guessed it, RIPE!
Pics please? Whole plant? Depending on where you are, I'd have to say its way too early, but then again we dont know where you are or what the plants look like so if you really want some real info please post some pics. thanks, and have a good weekend. jerry.