That’s sorta correct, as in the “hairs” or pistols are white when they first develop for most strains, and as they mature they whither down and darken. But yeah trichomes are the real thing to pay attention to, not on the leaves but the actual buds. Once you see them transition from clear (immature) to cloudy (mature) to amber (degrading) you can assess the ripeness of your flower. Most growers will try to harvest when they’re seeing 80% cloudy 20% amber or somewhere around that mark. Yes trichomes are a newer term for some of us (we called em crystals) , but I think it’s just a more technical term that as you progress as a grower you add to your vocabulary.
Terpenes are another term that I’d never heard before I started learning more about growing.