You're no expert. You shouldn't even be teaching, or creating a blog. Why would anyone read it?
Amazing how we start with a great idea and within minutes we're sure it was the dumbest thing anyone ever thought of.
If this is you, join the club. A very, very large club, by the way.
It's even got a name: Impostor Syndrome.
Now, it doesn't matter whether everyone tells you how good you are, how you really need to be positive, aim for the stars. They won't convince you, will they?
After all, you're an impostor, right?
Well, this blog is by people who themselves have suffered from the impostor syndrome. In some cases - maybe most of them - they still do.