is bipolar hereditary?

I don't know that it's been definitively proven, I am aware of a current study to identify any genetic links between parents and their children.

I can tell you, that to my personal knowledge - yes, it is genetic.  Not only with bipolar disorder, but if one or both of a child's parents have schizophrenia, panic disorder, anxiety disorder, major depressive disorder, and the like - the chances that the child will also suffer from some sort of mental disorder increase remarkably.

So short answer - yes.  The good news is that, now that your daughter is forearmed with this knowledge she can keep a close eye on her child and she will recognize the symptoms far earlier than another parent (like myself) would.

Good luck and best wishes.