Alivia's new word

So the past few days we've noticed Alivia repeating a certain four letter word. Bryan and Rob are the worst at cussing when the kids are around. They're trying to refrain but it's kinda hard. Last night Bryan was sitting at the kitchen counter eatting dinner and Alivia was sitting on the counter mooching off of him as usual. Bryan bit his tongue and said "Shit!" a few seconds later Alivia said clear as day "Shit!" Bryan's eyes got real wide and he said "Did she just say what I think she said" and I said "Yep she sure did" a few seconds later she said it again.
This morning I was walking into the babysitter's house and I was carrying alivia and her bag and trying to pick the morning gunk out of her eye and I went from the drive way to the sidewalk and kinda lost my balance and tripped, I didn't say anything but alivia said right away "Shit"

I'm not sure what to do I've been just kinda ignoring it, at least she's using it correctly!! ok just kidding but I really don't know what to do!!