An extension of stay takes months to be adjudicated, I'm certain she will not get a response by the end of her current authorized stay. So your call if you should still want to file for it.
Okay. So, let's say, she overstays for a month waiting for her extension to be granted and after a month of her overstay, if her extension comes out as a deny, then the days she has overstayed would be considered as unlawful presence. Will this "30 days or so of unlawful presence" be a problem during Consular Processing?