Oh, wait, I'm not the King of the Internet. Nobody is. There's nobody to give you permission or approval... except you. Go ahead and give yourself that permission - permission to write, and even permission to be wrong.
The thing is, everyone who writes on the internet has been wrong. Everyone. You aren't going to be this horrible exception, the one person who said one thing wrong on an otherwise-perfect internet. So go ahead. Write. Make mistakes.
But, as others have said, learn. When you discover that you have made a mistake, say so. Correct it, in public, because the mistake was in public. And don't feel horrible when you do. Instead, feel smarter than you were when you made the mistake.
You'll make mistakes. Do it anyway. Forgive yourself for the mistakes, learn, teach your readers, and move on.
https://www.amazon.com/Technical-Blogging-Expertise-Remarkab...
You could always publish under an pseudonym, then if things go well claim it under your real name.
Key really is getting people to read what you're postings and getting feedback. You might consider starting or including an option to get the posts via email, which will give you a direct way of contacting readers.
"develop the habit of letting small bad things happen" - Tim Ferriss
You blog will likely be ignored and never get more than a few visitors. Forget about being wrong because there is little chance anyone finds out. Also, who cares if you are wrong? What matters is that you dont stay wrong.
Here is my shitty blog:
Rejoice in the mountain of grammatical and technical errors.
Assuming you have any significant knowledge (and you probably do), the good you'll do by sharing that knowledge will massively outweigh the harm any mistakes may cause.
Just be open to corrections if they come up.
This sort of fear is very normal, and is what stops a lot of people from giving a lot of value back to the world by writing about their area of expertise. If you overcome it, you'll help not only yourself but also lots of other people.
Remember that many scientific papers published in peer-reviewed journals turn out to be wrong/not reproducible or contain errors .
If you're blog is about doing something that could be destructive (How to migrate data from X to Y) etc, just start with a disclaimer, and ensure you do as much testing as you feel obliged to do.