dude, there are no dibs on girls. Free game until taken. so if your friend hasn't asked her out yet go fot it. So what if you don't know her. I can garuntee you one thing. You will NEVER go out with her if you don't ask. True you might not even if you do. But, the point is ask her already. sheeh.
Take it from a past REALLY shy guy. Don't be a puss like i was.