I think you should consider what she is lacking, and address that shortfall with your choice of birthday present.
Giving something that provides for her long-term needs will, no doubt, be very welcome.
As Geoffrey Chaucer prudently related in one of his Tales:
Megan: buxom maiden lass
was feeding sheep in yonder grass.
Upon her birthday, Megan she,
had but a flock of only three.
While young Tom Shepherd had five sheep
and in top field he did them keep.
So when he, Megan chanced upon,
In t' long grass, he gave her one.
mmm depends what she likes really like if she likes to read maybe a book or if she likes make up or clothes or a movie just what shes into
Maybe nice jewelry? Starbucks gift card ;)? Cool T-shirt? Maybe a phone case? That book they've been dying to read?