Depends on a lot of things.
But it will change her, maybe a little, maybe a lot.
Did she ever fucked a big cock, doesn't matter what color.
If you satisfy her now, then you will satisfy her later as well. A pussy is a muscle, it always goes back to it's original size. Only if you fuck her right after the BBC, then it could be that she doesn't feel you and therefore does not get satisfied with you.
If she will be wanting BBC all the time, that is what no one can predict.
You wanting cock, well, that also some we cannot predict. Is it something you want?