To but it bluntly, the sooner you start making your comic, the sooner you will start gaining experience in the field. Putting it off can 'potentially' stunt your growth as a comic artist (I say potentially because like all things, the learning curve and method is different for everyone)
I was stuck in that spiral for a while, I never felt like I knew enough about making comics so I was never good enough to release them. (redrawing the first chapter over and over and over again because it was never good enough) A big part of that was that I didn't know what I was doing wrong, I knew I was doing SOMETHING wrong but I just didn't know what, because I did not have any experience in drawing comics.
Eventually I started releasing them despite my lack of experience even though I knew that I needed to work on things or that I didn't know how to do things. The thing is, when you post stuff online you can get critiques from readers and people that have experience making comics, you can learn from the mistakes that you made and incorporate them into your next pages. I've come a long way from when I started and learned a lot, it actually hurts to look at the first chapter of Raven Wolf because now I can spot all the mistakes and things I did wrong (not in concerns to drawing, but comic layout and word bubbles and story telling methods) but it also shows how much I learned and my progress in doing so. It's something to be proud of.