No, PIR will never be on a Saturday. PIR is always on Friday unless a federal holiday at the end of the week moves it up. You will not regret taking the time off.
By counting 9 Fridays, her PIR will most likely be 08/14/2015, but it could also be 08/21/2015 since she will be arriving at the end of the week. See Arrival and What Happens at the RTC.
If you really want to go, then you will make it happen.
You surely will have built up vacation days by then.