First she needs to decide what she wants it for, race, train, sportive, leisure ride, commute etc etc. Then she needs to make sure she gets a bike that fits her properly. Planet x, ribble etc sell perfectly good cookie cutter carbon framed bikes but they may be completerly unsuitable for the riding she intends to do. This is the sensible advice.
The less sensible but more atractive view is to be seduced by carbon and shiny groupsets and blow nearly £1000 on an unsuitabe bike you have never sat on from the internet.