This is incorrect. Most cannabis plants do not produce CBD. What you are thinking of is CBN, which is what THC breaks down into as it degrades. HOWEVER it takes a significant amount of time for that to happen. It takes weeks for plants to ripen not days.
Don't be confused you shouldn't be listening to peoples opinions. YOu should be looking at the plants and how they are progressing. Here is the basic rundown I share with new growers.
Before even thinking about harvesting take a look at this and see if your plant is actually showing you all these signs.
The signs of ripeness are pretty standard.
First a few of the pistils begin turning color and start receding. Your plant is just starting to ripen. Depending on the strain you could still have two months to go. We're just starting this journey.
Two to four weeks later you'll notice that most of the pistils(>80%) have now changed color and curled back into the bud. It's frosty, way bigger than it was a few weeks ago, and smells dank! It's time, right? Not a chance killer. Patience is a virtue
Over the next 2-3 weeks it doesn't look much different, maybe a little more swelling in the calyxes, and the rest of the pistils change over, but the stems ars starting to bend under the weight of the buds. These ladies are putting on weight and now the buds are doing their final ripening.
Now you begin looking at trichomes, on the calyx not leaves, and harvest according to your preference. When looking at trichomes it’s essential to look at them from the side. The bulbous heads can magnify the opaque stalk under it. Looking from the side allows you to more accurately see the condition of the resin in the trichome head.
There is still no rush to harvest, the window just opened, and you have several weeks before you MIGHT start having to think about it possibly beginning to get too ripe. It takes WEEKS for plants to mature not days.
It is very easy to harvest a plant to early. It is very hard to harvest a plant to late. I’ve never seen someone accidentally wait too long.