Yes, this is normal. Obviously don't take at face value her denial of having questions. It's not at all unusual for children to say they have no questions when, in fact, they do. Take a look at the range of children's literature about sexual developement and select something suiatble for her young age and then read the book along with her. Also let her look at the book(s) herself.
I'm going to be honest.kids are not kids anymore.in my opinion an 8 yr old should be curious but not that curious.I would definetly talk to her (and only you know what to say to her) because trust me a boy will talk to her and persuade her because they are twice as curious.