This book is a pretty light and easy introduction to Go. It's also available in print which is how I preferred reading it.
http://www.golang-book.com
This book is a bit tougher, but it's short and really well written. I think it's overall the best book currently available for learning Go, but if she's new to programming I'd recommended that previous book first.
http://www.amazon.com/Programming-Language-Phrasebook-Developers-Library/dp/0321817141
This book covers the language pretty in-depth, but it's long, dry, and difficult to read from cover to cover. It can be quite handy as a reference for details about the language.
http://www.amazon.com/gp/aw/d/0321774639
There are a couple topical books that and a couple other not quite as good introductory books that could also be quite useful to so anybody who can't get enough Go. Go is in my opinion the best overall programming language, but if she's interested in programming games and graphics and such, Scratch is a drag and drop programming environment targeted toward 8-16 year old kids in school, and this is really great Python book written by a father and son. The linked page has a link to the newer edition of the book that covers the newer, but sometimes less liked Python 3.
http://www.amazon.com/Hello-World-Computer-Programming-Beginners/dp/1933988495