Confused and need some advice.

So I(27M) work in a family owned business, and about a month ago I interacted with what I believe was the most beautiful girl(26F) I’ve ever had the chance to meet. Every bit of interaction we had was incredible. At this point I’ve learned to distinguish between common courtesy and just flat out interest in me when interacting with customers, this one was the latter. Everything seemed to flow so smoothly, and she kept finding ways to spark conversations with me so casually. She was dining with her family(parents and younger sister) so I automatically removed the idea of asking for her contact info and now I feel as though I made a mistake. Haven’t seen them since that day and on occasion the thought hits me.

Just looking for some advice to either prevent this from happening in the future, or maybe even how to handle the situation should they ever come around again.