Get a cheap pocket microscope from Radioshack... It's the best 12$ you'll ever spend.
Seriously, I've seen grows where the pistils (large hairs) were completely white - yet the trichomes (what you need to be looking at) were almost all amber... I've also seen grows wehre the pistils were completely dead and the trichomes failed to mature for 2 further weeks.
The only way to check, is to look at your trichomes under a 30x or higher microscope.