Should I message a girl I met?

I met someone at a book club meeting last night and got on with her well. I think she maybe likes me too. She is really pretty and we have stuff in common. I don't have her number but I could contact her through a group social network of which we are both members. She is ten years younger than me and I don't want to come across as creepy. I'm due to see her in a couple of weeks at the next meeting.