If this is your first attempt, I think you did a fantastic job. It's beautiful and you should be very proud of it!
I've found it's true that most of us are overly critical of our own work, for some reason expecting something more than we end up with. I'm learning to step back and look from a slight distance and find that what I deem to be mistakes are simply not the perfection I demand of myself, yet nobody notices it but me.