I like and admire this post, which I came across on Twitter, from Mary Cecilia Jackson:

I started writing what I WANTED to write at 54. Began with picture books. They sucked hard core. Found my YA voice at 56. Got an agent when I was 59. (It was HARD.) My debut comes out in 2020. I’ll be 62. There is NO age limit to your dreams. Write on, lovely writers. Write on.