Don't be so hard on yourself. It's fine! It's the speed you move the quilt that does it. It takes time to get the rhythm down. The more you practice, the less needles you will break. I don't break them very often, but still do on occasion. Once it's washed, you'll hardly see what you now perceive as imperfections.
I found that when I first started out, there were shape I was pretty good at (loops, swirls), so I stuck with those to build my confidence. It took many quilts before I could do a decent stipple. I still don't like to do stipples though. I have a hard time keeping them consistent in size. It also took a while before I could stay on the lines to follow a pattern. That is easier now too.
It's good that you tried. So many people are dying to try it, but afraid to. The worst is over, now you can relax and keep practicing!