That's just the way some bitches are! It's also possible that she just wants to explore a little and has learned that as soon as she goes, she's taken back inside. She's learned to prolong her time outside exploring all those good smells by waiting till the last minute to go.

Toy dogs like some time outside too!

To train her to go on command; the instant she squats to go, use your key word, then praise her when she finishes. If you're 100 percent consistent, she'll learn to go on command in no time.