Context is also kind of the key. She gave you her number but you were giving her the possibility of getting information and possibly leads. If some random guy was able to offer me job leads given the current market I'd probably give him my number, fax, phone, three emails, url and my first born child (okay maybe not...). So there was also some incentive going into that number beyond just "hey you're cool here's my number". :)

That said, however.. she chose to stay and talk with you rather than go with mom, which meant that rather than just handing you her info and bailing (if all she wanted was possible leads), she chose to hang out with you and talk. So that indicates that she was indeed enjoying your company and chose enjoying your company over going off to do something else. This is a Good Sign(tm).

My advice? Don't play mind games. Don't wait X amount of days/hours/minutes. Give the girl a call and chat with her. If she is as friendly and wants to chat with you the second time as she was the first.. then you're on a roll. But I have to agree with what some other people have said. Have confidence in yourself. Go into it with the attitude that "hey I met someone neat, and I'd like to stay in touch, but if they're not interested in me well that's okay cuz they're still groovie and it was a good experience" :)

So while I would not assume too much, I wouldn't assume too little either. Just call and give it a shot. :)

*hugs*