Often, when my husband wants to buy me gear, he will give me a picture of what I am going to get, and then we go to the store together and I pick out what I want.

Bikes are awesome. She will LOVE being on a bike. Personally, I love my carbon, and I am glad that I did a big upgrade after my aluminum hybrid. Granted, it always gets love and time, and it wasn't a waste. If you KNOW she is going to really enjoy riding, I am on the "buy the nicest thing you can manage and fits her," camp. She can "grow into" a nicer bike, and will appreciate being able to do that. Otherwise, you will end up buying more than one bike, and the cheap one will sit in the corner.

That's my opinion though....