Being offered that job in Las Vegas was my lucky break. I have never looked back!
What does I have never looked back mean?
Look back here means that you would wonder afterwards if you made the right decision.
When I look back at my life, I wonder if I would do things the same way…
If you say that you never looked back, it means you are so happy with the decision that you took, that you never even thought about whether it was a good decision or not afterwards.