It seems obvious when you read it, but if it really were that obvious it wouldn't need to be said, would it?
I personally was sitting on that wall for a while. Then I realized at some point that I was waiting for some sort of collective "permission" from "actual writers." When I type it, it sounds like utter codswallop, and it is. But the mind will go a long way in its quest to keep you out of perceived danger.
Once I realized that I didn't need anyone's permission, I just wrote, and I posted the product of that writing on here. And it was probably pretty rubbish. But I took the damn step, and that's a big deal, psychologically. I wouldn't ever discourage someone from doing it.
Even if our writing is rubbish, that is okay. That means the only direction we can go is to less-rubbish writing!
If we start at the bottom, we can only go up from there.
That's exactly it. You can't get better if you don't practice, after all.