Get her the one she thinks is the prettiest/coolest to ensure she will want to ride it the most. All of those bikes are nice bikes and honestly for a 14 year old, she couldn't go wrong with any of them. I will be jealous of her. If she is just getting into cycling she will hardly be able to tell the weight difference between the bikes anyway. If she has no preference on the look of the bike ( I find this hard to believe from a 14 year old girl) I would grab her the most comfortable and durable bike.