This is one of the many reasons that I'm not on Facebook.
But that aside, I would delete it and tell her why. I would caution against inferring what her intent was or "accusing" her of anything. The truth is you don't know why she wrote what she wrote. It may have been malicious or just thoughtless. Instead, just tell her that, true as the statement may have been, it hurt your feelings and that out of both concern for your parents' feelings and your own, you took the message down. If that ends any further "friendship" via Facebook or otherwise, then so be it. Life's too short.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher