I applaud the original post for the positive note it has sent throughout the thread. Writing is a personal endeavor, and in the early (learning) stages, comes with few back pats.
I do have a caution to mention, and that has to do with combining ego with writing. It can create a slippery slope if it is allowed to stray too far from the confines of self-confidence. Some people have egos that extend well beyond their demonstrated competence, and this is an important point for us all. I would rather not state to the world that I'm a great writer. What I am is a devoted writer, which means I am working hard to not only establish my competence in writing, but to constantly increase that competence, to constantly challenge myself to improve in the craft and in storytelling. This also means always setting new goals, sometimes experimenting (even though some experiments fail), and always paying attention to how my work turns out and how it is received. So where does ego/self-confidence work into this? Both should come from more than just a singular activity like writing. What we do outside of writing is just as important in both ego and self-confidence formation as what we do with our writing. For many of us, our personal self-image was formed long before we put pen to paper (or fingers to keyboard), and it's not likely writing, in its early stages, will do much to alter that in one giant swoop. We can tell ourselves that we are great writers, but I'd rather ask myself what I've done lately to work toward being a better writer. If the answer is a shoulder shrug, I'm not a great writer. If the answer to my question is that I'm trying to improve in the following ways (include personal list), I can say I am working to be a better writer. And if I can look back at my earlier writing and see how my current writing is better, I have that sense of accomplishment that gives way more than lip service to my desire to be a better writer. It shows I am doing it. That builds self-confidence in my writing world without letting my ego get ahead of my accomplishments.
Personally, I will never tell myself I'm a great writer. I'm satisfied to say I'm showing improvement in my writing because this addresses realistic short-term goals. First drafts are getting closer and closer to final drafts. My writing toolbox is expanding. I'm trying new things, even if they fall flat. I'm having more fun with my writing, and getting that sense of creative accomplishment when I work through the tough spots and sticking points in my stories.