1. Nancy Drew was first created in 1930 apparently, not the 1960s as we believed! She was 16 originally then became 18 when the series was revamped. There have been a number of authors, all using the psuedonym Carolyn Keene. You can read more at wikipedia.

2. After reading the new book, I read an old one again (old being from the 60s/70s). The new one is much better! Although the basics are the same, the older one seemed rather patronising to me (as an adult) whereas the new one was just simple.