It wasn't until age 50 that I gave in to my long-standing desire to write professionally.(as I write this, I'm not sure that I am "professional" yet - I haven't sold a copy of my debut novel, released today!).
I'd put aside time each day to sit on the balcony with my index finger and my phone, fleshing out the scenes I had envisioned before falling asleep the previous night. It took me three months to write the ~150,000 words, a further nine months to be happy with it, a couple of months deciding on the best way to publish (spoiler: I went with Draft2Digital), and then another month until I was happy with the layout of the finished ebook file.
I know there's still a lot of work to do (aside from finishing the other books in the series) in marketing, maintaining my social media profiles, begging for reviews...but I'm really happy with what I managed to produce, and my enthusiasm has not waned.
Watch this space for the next books!