So this weekend I'm at a festival, and last night I was taking the bus home and some girls entered the bus and one of them was singing/mumbling the lyrics of the song that was played in the bus. I looked at her and smiled, cause i thought it was funny. She smiled too and thats all, We both were sitting at our seats, waiting. Like 5 minutes later when we were on the road a random girl (I think one of her girlfriends) came up to me and handed me a paper. It was a name and a phone number. I thought I'll text/call her today and if she's coming we can hang out tonight. On the other hand I thought that maybe I should have texted right there to call her to my place. My question is that what is your opinion in situations like this? Wait a day, or not?

tl;dr: Random girl gave me her phone number on a sheet of paper on a bus, going home from a festival. Should I have texted her right there, or it's better to wait a day?