Got a request for these at our local store, and so was curious to see what they were about. I quite enjoyed the story overall, though I do have a quibble. This girl is 14 (just turned, no less), and manages to get herself into - and out of! - situations that would more fit a protagonist in a YA story. There is no romance or anything sexual at all - but her escapades and how she gets through them really tested my suspension of disbelief at times.
Having said that - I *did* enjoy the story, and I can definitely see that there would be an audience for them. Enola is bent on showing her older brothers (whom she's only met a couple of times before) that she is NOT of lesser intelligence, and she refuses to be forced into standard society nonsense. It was a quick read and as there are several more in the series, anyone who enjoys the first can head straight into the second.