Ask her what life was like for her as a child (a general question). Depending on where she grew up, you can find out a lot about what city life was like then or country life. This type of discussion will help you think of many other questions to ask about city, town, or country life.
Ask her what her parents did for a living.
What is her favorite memory from childhood?
What were some games she and her siblings and/or friends played?
What were considered luxuries then?
What was school like?
What did her parents teach her to treasure most? (For instance, when my mother was little, books were important because they didn't have the money to buy them so when someone gave them a book, it was a tremendous thing.)
Ask her about food -- what food did she like best? What was something her mother or father made for them that was a family favorite? This can open up a lot of discussion over types of food as well as costs and what was available when she was a child.
Depending on her age, ask her what effect, if any, WWI or WWII (or both) had on her family. Ask if it made a difference in everyday life for her as a child or if they were kind of cushioned from it.
You'll get ideas for more questions once you two start talking --- I'm sure it'll go much smoother than you think. And believe me, you will get much more out of this than you think also -- you're doing a nice thing going to talk to this person, but you're also doing yourself a great service -- you're going to be listening to "living" history....it's a wonderful thing. Enjoy it.
Good luck with your report!