I love my boyfriends mom, she's cool and has never been rude to me or anything and helps me whenever…

I love my boyfriends mom, she's cool and has never been rude to me or anything and helps me whenever she can. But sometimes she'll joke when we say something about "her unborn grandchild" and say "we don't know if that's my grandchild yet, wait to the maternity test. We're gonna go on maury" I know she's joking and she loves that show but it just makes me feel awkward when she says it.