My stepmom is 7 1/2 months pregnant and is about ready to pop. What can I do to help encourage her?

I'm 21, and I live with my stepmom and dad (I’m not enrolled in college, but I am istant manager of a lingerie boutique in my town. I have plans to move-in with my buddy by March of this year). My stepmom, who's 29, is about ready to give birth to her first child--a boy. It's my dad's and stepmom's first child together and it's my first sibling (I never would have thought that I'd be getting a baby brother in my twenties...lol). The thing is, my stepmom cries almost every day, and she always comes to me and tells me that she doesn't know if she can be a good mother to her baby. Every time she tries to confide in me, I'm always at a loss for words. The only thing I say is that everything will be great. As a stepson, what can I do or say to encourage my stepmom to make her believe that she'll be a great mother?