I make mistakes all the time. They're usually minor infractions, like forgetting to put the recycling out or leaving my iPad on in my bag until it goes dead. Normal life is a safe place to make lots of mistakes. Making mistakes in the business world can be costly. I once trusted a client's proofreading skills on a $1200 folder order. I'm sure you can imagine how that went. It wasn't my fault, but it was my fault, you know? I learned, and proofread everything clients send me now, whether they claim it has been proofed or not.
The goal isn't to avoid mistakes, though, but to learn how to recover from them. My daughters are learning this as they play outside. It's not about learning not to fall down, but how to get up and move on gracefully. In the real world of work and clients, our ability to master this skill is critical to the longevity of our business.
That botched folder order that wasn't my fault? I issued the client a very large design credit that they dipped into and used for the next five months. They still had to pay for the folders again, but they got to use my services for free for a long time thereafter. I recovered, and the client was still delighted.
You're going to fall down. Learning how to get back up is the true secret to success.