I was talking to this cute girl at Starbucks (I think she works there but she wasn't working at the time) and it was going well. We were laughing, eye contact and all that. Then there was a bit of a break in the conversation and she said it was nice talking to me, I said seeya and she left. I forgot to ask for her number because I was into the convo, but I still want to get to know her. How long should I wait until I go back so I don't look like a desperate bitch?