if she lives in a rural area it could easily have taken that long...my daughter lives in the country and when i lived 9 miles from her i sent something to my granddaughter one time that took 9 days to get there, i guessed the mail lady was walking....a mile a day....
it can be aggravating but when you are at the mercy of the postal system you just have to wait. and if she sends the book parcel post it can take a month to get to you. my recommendation is if you are going to order through the mail to always use delivery confirmation; that way the item in question can be tracked.