Where did I go wrong? Options

[dpl313]

It all started when I went to this phone store to see about buying a phone. I met this girl. Let's call her Mia. Mia had a long convo about phones and other stuff. You could tell there was a good vibe going. I should've asked her for her number then. Next time I went into the store I asked her about some phone stuff, and then I asked her for her number. She gave me her card which had her cell number on it.

I waited a day and then I called her. I called once or twice for 2 days. She never called back. I went to her store 3 days after that. I went up to her and I asked her out to lunch. She just looked sort of smiled, blushed, and said she's very busy that day. I said about what about another day. I felt like she just kept coming up with excuses. So I just left. I felt pissed and dejected. Mainly because why give me your number if you don't want to be bothered? That and if girls like guys with confidence why didn't this work out? Was it something I should work on?