Is it ok to correct her grammar?

I know a young woman who is rather grammatically challenged. She often uses very poor grammar that just makes me cringe. She is in college and wants to be an early childhood educator and it seems the poor grammar could be a huge obstacle to achieving that career goal. Whenever I hear her say she didn’t go nowhere or that she seen someone at the mall, it takes all my self-control to keep from correcting her. Is it all right to gently correct her or should I just keep biting my lip.