Thanks for the post, you've always been an inspiration to me ever since I started.
Like you, that didn't happen until I was over 50, and I had never written fiction before, never read a craft book and never heard of self-publishing. Being dyslexic didn't help my confidence much either. But I read a lot and just wanted to write more of the stories I like to read. My first book went nowhere, but that was OK. Even just to finish it and publish was a major achievement. However my next two books took off, I don't know why exactly. I didn't study the market, I just wrote what I like, the way I like.
So I'm planning to go full-time early next year as I'm now earning more than my day job, and all my friends who thought I was crazy to write are now giving me strange looks... and asking advice.
I may not reach your level of success, but it's feels great to be where I am right now... all because I said 'why not?'