Overall, I think your plant is pretty healthy. The "buds" might be small and there is some weird leaf shaping. I'd say that's largely due to lighting or temperature issues that might be effecting your yields. I have found the best way to harvest is by getting a microscope on amazon. Something to look closely at those trichomes. What to look for? Well it depends on the kind of "high" or "effects" that your looking for. Trichomes will start off small then stretch into a long looking clear mushroom. Eventually, they will change to a "Milky" color in the bulb of the trichome. After they are all milky in nature, you can harvest. This is a earlier harvest and it will give you more sativa like energetic effects. If you wait another few days after that milky turn, they will start to fall over and become amber in color. If you harvest when there is a 70/30% amber to milky ratio, that will give you more of the indica "couch lock" effect. More of a nighttime smoke. Note THC is at its most potent stage when the trichomes are milky. Also note that on the grower website where you got your seeds, there is a "Flower time" usually listed. This will give you a rough time frame of how long the plant should be in flower. You shouldn't have to check until the last two weeks of flower in most situations.
Hope this helps!
Cheers