Sailing lessons are not going to prevent you from "making your own ... mistakes." You will make mistakes. Hopefully, the lessons will give you enough background to recover from them.
I'm not talking about racing tactics, but the essentials of safety, weather, rules of the road, etc.
Unless your sailing in your bathtub, your mistakes will pose a risk to yourself, your passengers, and everyone on a boat nearby. Would you tell a novice driver to "just get on the highway and make your own mistakes?"