I would never describe Charlotte as a prude - maybe at the start, but that was in comparison to the other girls. She wasn't willing to do the stuff they were doing - and I mean, thank goodness!
Unless you're involved with thinking about what you're doing, you end up doing the same thing over and over, and that becomes tedious and, in the end, defeating.
As long as you're having fun and still doing stuff, it doesn't matter what other people think.