One of my favorite authors started writing fiction for publication well after age fifty, I believe. Her experience, and listening to and reading exhortations to aspiring writers, may have prompted her to say this, with which I heartily agree:
Spend some time living before you start writing. What I find to be very bad advice is the snappy little sentence, “Write what you know.” It is the most tiresome and stupid advice that could possibly be given. If we write simply about what we know we never grow. We don’t develop any facility for languages, or an interest in others, or a desire to travel and explore and face experience head-on. We just coil tighter and tighter into our boring little selves. What one should write about is what interests one.
~Annie Proulx~
Write what you want, I say, but be prepared to hear critiques that may miss the points you’re making. By the same token, don’t dismiss criticism out of hand because it seems to miss the points. Whatever you do, don’t be bound by what someone tells you about writing, including this.