Robert Allen once said anything worth doing is worth doing poorly. In other words if you what until you can do it perfectly you will never do it. It's better to do something than to do nothing. Most of the time you can adjust or fix things. I have found in playing music in front of people, usually they don't notice my mistake unless I react like I made one. It's good to do the best you can, but being human you will never be perfect and that's ok.