I can't think of many exciting adventures featuring girls for that age group, no. Novels for slightly older children, though, tend to be ruthlessly equal opportunity about things, and usually offer a matched pair of main characters. It's strange that there isn't more exciting female adventure for young children, since there's plenty of it in adult fantasy writing. (I speak as someone with a ridiculous aversion to female main characters in adventure stories, who abandons many a book after just the blurb.)