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Ok, so I think I may have missed the mark asking this girl out (which I need to leave for here in about an hour)

Anyways, I met here at work and we used MSN to communicate at work...we go to lunch every now and then. I am no longer working there, but we have still stayed in touch via MSN. I asked her what she was doing (this is all on MSN, because I dont have her phone number the way I would have rather done this...) she said she didnt have plans, and then she asked me.

I told her I had just bought tickets to an event, (which I hadnt yet) and asked if "she wanted to go." She said "she would love to." I told her we can grab some dinner before we go. Now yesterday I IMed her briefly, and she told me to call her today and let her know the plans. I called her and told her to be ready by 5. She said ok, and asked where she should meet me...
Thats what got me thinking, she has the impression that we are just hanging out?

I said I will come pick you up. So she said to just give her a call when Im leaving at she will give me directions.

I think I may have answered this question while typing it out. But if she does think this is just 'hanging out,' do I stick to my original intentions and treat it as a date, or do I sit back and do it as friends would?