Well, if it’s any consolation, half the time I don’t feel like my art’s good enough to be posting all over the place, either. Yet here we are : >
So really, you might be super nervous about it, but nothing’s gonna happen if you don’t post anything! There’s always a risk with putting yourself out there, But if you never post your work, nobody’s ever going to see it. So you won’t get any negative reactions (or ambivalence), but you won’t get any positive reactions, either. It’s a bit of a wall to get over at first, I know.
Just remember that you’re constantly improving, as long as you keep at it - sometimes I look at my drawings from even a month or less ago and wonder what I was even thinking. So I say to just go for it!