That is so sweet. I'm sure she will love it!
I received my first diamond on my 16th too. It was my great grandmothers engagement ring, and my birthstone. (Family tradition to receive a genuine birthstone ring on your 16th)
I absolutely love it and still wear it today, which is pretty big for me since I am not crazy about Jewelery. I only have 3 things I never take off... The diamond ring, and my Engagement ring and Wedding Band.