Well, posting on Tapas wasn't necessarily my first rodeo with posting online. I started posting fanfic on Livejournal in... what, 2005? 2006? Anyway, a millennium ago in internet terms. The fanfiction world has gone from Livejournal to Fanfiction.net to Wattpad to AO3 since then. When I first started posting, I was terrified every time. I definitely posted some stories and then immediately deleted the because it was too scary. If I saw a comment, I might avoid clicking on it for several days because I was too scared it would be someone systematically tearing down everything I had worked so hard to make.
I have always written original fiction, but back then I didn't know where to post that online. There just didn't seem to be an audience for it (whether there is an audience for my particular original fiction is still kind of up in the air, to be honest). Sharing original fiction is even scarier than sharing fanfiction. I took creative writing classes and eventually went to an MFA program, but still, every time, I nearly had a panic attack when I had to hand in a story. My friend used to give me Klonopin to take before we critiqued my story in class.
But, well, over the years you get slowly more comfortable with yourself and your work, I think. I still get excited to post, but a lot of the terror has (thankfully) seeped out of it. Now I don't attach so much of my worth as a person to my talent as a writer, and I also don't attach so much significance to other people's opinions. I'm a lot more open to opinions. I find the worst thing now is people being indifferent to what I've written. I relish strong opinions of any stripe, and I genuinely crave the opportunity to make my writing better. It's the sinking into oblivion now that's the true terror.