I started a software business in 2003 catering to mortgage brokers. Sold it in 2008 for 7 digits.
I have been managing it since then which bores me. I like to control my own path so I just handed-in my resignation and will start another software business.
I'm 54 and don't let anyone tell you you're too old, or any one of the other million excuses. Backing yourself is the only true security.