It's great that you're thinking about these questions now. I think your focus should be on what it means to have a healthy dating relationship. How can you date in a healthy way.
Are you dateable? https://www.amazon.com/Dateable-Are-You-They/dp/0800759117/ref=sr_1_fkmrnull_1?crid=1M64F8NBAGAH9&keywords=are+you+dateable&qid=1552223287&s=gateway&sprefix=Are+you+dat%2Cstripbooks-intl-ship%2C185&sr=8-1-fkmrnull Is a book that focuses on how to date in a healthy way and it's designed as easy reading for teens. It helps you think about dating in a healthy way.
I caution you on books that use a courtship approach. Even Joshua Harris doesn't support courtship anymore. There's a video on YouTube about it. I'd encourage you to consider a variety of perspectives on dating. You can also ask married adults how they did it. What boundaries did they have in dating? How did they keep a healthy perspective? What do they wish they had done? Get a variety of perspectives.
Buy her these books and let her figure it out for herself. https://www.amazon.ca/Dateable-Are-You-They/dp/0800759117/ref=sr_1_1?ie=UTF8&qid=1534719776&sr=8-1&keywords=Are+you+dateable