Did I just mess up? And if I did how can I fix it?

Hello reddit,

Tonight I was walking a member of my trivia team home in the bitter cold and when we arrived at her place she invited me in to get warm before I continued on my journey home. I went up, grabbed a glass of water and conversed a little then I said I had to go. She seemed a little shocked at this and said ok and I left. I hadn't gotten halfway down the street when the thought occurred to me that she might want to do a little bit more then conversation. I am really terrible at picking up hints and I just got out of a three year relationship and this is the first time anything like this has happened to me. I admittedly have a bit of a crush on this girl but never thought in a million years she would be into me. What do I do now? Nothing like this has happened to me in three years so I am super rusty.