The trichomes check is a good way to tell if your harvest is done, but it's not always a guarantee. The white pistils will retract, turn orange (or another color depending on strain), and look at the calyxes. As the harvest time gets closer the pistils will change color from white to rust-colored orange or brown. This is a sign that your plant is at the end of its life, and is ready for harvest. If you look at your pics, you can see that your pistils have much longer to go. You should have not only let the bottom go longer, but the entire plant. To me the important thing would be that your plants don't look like shit, and you were really only a few weeks away. If you wait longer next time, you will have a decent little harvest. You should also try some training and lollipopping techniques to get some bigger colas next time.