Mistakes are made so we can learn. One way that human beings learn is through making errors. We call this trial by learning. Ask them why pencils have erasers and why we have White Out. Highways have U turns so we can change our mind if we go the wrong direction.
Mistakes are for learning.
It is okay to make a mistake, if you learn something from it. It's a much better ideas to use your energy learning from what you did wrong instead of beating yourself up. Figure out what you did wrong. Figure out what you can do differently next time. Correct the error.