Temperatures, even freezing, won't slow the maturity of your buds. No worries. I'd wait another week or two then start defoliating the fan leaves. Don't worry about the color of the trichomes.
If the trichomes are clear, they're mostly CBG. THC, CBC, and CBD roll in at cloudy. Amber ads CBN, which are in my opinion critical for a great high. I have yet to hear anyone say "you harvested too late/early" after a toke.
After I saw my first weed plant growing, I could spot weed in a field from the corner of my eye as I drove past. It's the same with a mature flower. Once you see them, you'll know pretty easily if they're ready. IMO, most home growers harvest way too early, so they never get to see them in their full glory.