edit I also didn't explicitly say what @jeromec did, but I definitely share his sentiment. You owe nobody an apology for the success that you had and will hopefully have in the future.
Playing it safe is one way to get ahead in a sure and steady way and I'm quite sure that the way you've positioned this project and how you handled yourself in the execution of the project and the subsequent sale does nothing but confirm the fact that you have what it takes to be a successful entrepreneur under his own power.
Don't forget yourself either, though. People like you are the guys behind every success that happens. You've always been there to help. So thank you :)