I'd say dont mention it to her again. I believe ignorance is bliss, unfortunately Im too smart for my own good and dont have much ignorance! After her first birth she will decide whether she should watch the DVD or not.

I stressed myself quite a bit earlier in the year when two of my sisters had their first babies. They were both quite happy to let their OB lead the way Both ended up in c-sections, but one Im sure could have been avoided, BUT, my sisters are both happy with their births, and thats all that matters i guess