Take this from a guy that has BDP (Borderline Personality Disorder) with a dash of anxiety and depression. Sometimes you can do everything right (cold contact, flirt a bit, ask for her number, set up a date, etc) and she'll still flake. Was she really busy that day?? Did she have something SO important to do that came up last minute?? Did her dog REALLY die?? Honestly idk and at the end of the day actions speak louder than words. I COULD give her another opportunity and a second chance but wouldn't it be better to use my time and energy for someone that's actually interested?

I have a habit of overanalyzing every small detail in my life (for better or worse...mostly for worst), but after reading some Stoicism and adapting the principle on actions being out of my control, it has given me comfort and solace. Maybe I wasn't her type, maybe I came off a little too strong, or maybe her dog really did die and I'm just an asshole for not giving her time to mourn.

Bottom line: Don't beat yourself up if she flakes. At the end of the day that's her decision, she made her choice and the only thing YOU can do is wish her the best.

Stay strong warrior!