When mine won't go outside within 5-10 minutes, I bring them back immediately to their crate for about 20 minutes, and try again.
I keep repeating until they do their business outside, and they will.. it just takes lots of patience and persistance.
Also, when you are outside don't talk or play with her. Just stand there quietly and wait until they do their pee/poop. Say "good potty" or your phrase you use in a happy voice and treat.
GL