How can I talk to this girl?

So yesterday I went bowling with some friends, and there was this really cute girl there. She seemed like the quiet/shy type. I didn't know some of the other people there so I didnt talk much, and her brother was there too. I'm 23 and she just graduated high school so I'm not sure if she is 17 or 18. A friend of mine is friends with her brother and stuff, so I don't want to make things weird for her. I found her through a friend on Facebook. Would it be alright to send her a message or should I just layoff? I don't want to seem creepy or anything. I really am a nice guy.