Not having produced a best seller by 23 (or 36 or 54) is the least of your worries.
"Failure in writing is not like failure in business, where you lose money and have to fire everyone and remortgage your house. When you’re a writer, most of the time, people don’t depend on you to succeed. Although you may starve if your books don’t sell, or your agent might yell at you for producing something that three people will read, failure in writing is more of an intimately crushing day-to-day thing. O.K., minute-to-minute. Measured against your ideal of yourself."