Birthday Gift for My Office Mate's Daughter

I've I got an invitation from my office mate to come to his daughter's sweet seventeen party on last Sunday. It took place in a restaurant not too far from my house. I wanted to come to the party, but I felt something wrong with my teeth or gums. I couldn't open my mouth, it felt so sore.
If I hadn't gotten a toothache, I would have come to the party.

I decided to give her a birthday gift, so I went to the mall yesterday before the Mandarin class (little bit late :p but I hope she can understands since on last weekend I just stayed at home). ["I hope she understands" and "I hope she can understand" are both correct.]

I went around the mall and tried to find the best gift. I became confused because I don't know her. we've just met once on at my office Gathering party. ["gathering" does mean people coming together, but we (Americans) wouldn't use it like that.] she is tall, white-skinned, thin just like that.

What gift do you thing best for her? T-Shirt, doll, shoes?

Good luck choosing a gift!