The final 2-3 weeks of a plants life makes a huge difference. You can't put arbitrary time frames on how long you flower them for. You need to let them grow and properly finish. Without seeing what they looked like at harvest its hard to say for sure. Really though those pictures look like they could hav ebeen pulled early for sure. The hairs are still standing straight up on the buds, and the bracts(calyxs) don't really appear to be very plump or swollen, which usually means the plant needed another 2-3 weeks to PROPERLY ripen.
Being your first grow its awesome you got a plant to harvest! The next step is watching all the stages of growth so you can really appreciate whats happening to the plant. Once you figure it out, and you get a plant to full maturity you will definitely appreciate what I'm saying right now even more. THE BEST smoke comes from healthy fully ripened plants.
Next time you think you are getting close to harvest, post pictures and we will try tohelp you dial in the proper time frame.