Either one will probably fit. I'm generally a fan of going with the larger frame if both fit. But your daughter has long legs so reach could be an issue on the 19". There's only so much you can shorten reach with a (shorter) stem. I would advise you to have her sit on the 17" before buying and set the saddle height using the heel lockout method (video below). If the position is comfortable (bars aren't too low relative to the seat) buy the 17". If it's uncomfortable repeat the process on the 19".

Heel Lockout Method (FFWD to 1:40)
http://www.youtube.com/watch?v=VrZBjOloChg&feature=youtu.be&t=1m40s