The young woman is an icon there (and elsewhere), loves to play to the crowd, and has fun with it. Good for her.
That's quite a crowd, and it looks like a pretty course, a bit more wooded and rolling than I'd imagined for Iowa.
From other videos I've seen, Caitlin and best friend Kate Martin play a lot of rounds together and are as fiercely (yet friendly) competitive on the course as they are against Hawkeye basketball rivals.