what kind of birthday gift should i give her?

If you want to surprise her, I will recommend you to make something by your own and don't think about the money- if it's not so expensive, it doesn't mean that she want like it. You should know what she dream of or what she want most. So think about and make something.

Hello I too agree with the responder above..you have not made that clear - to whom you wished to give a B'day Gift..as thats matters a lot..and if you know her fro a long..you must have known so far, all what she liked and simply get her the same..and in case you are not much familier of her likings..and even you could ask her now, what she would like to have as a gift from you on this special day of her life..To me, simply spending time with her, sharing many unsaid moments at a pretty place, you both liked would also be a fantastic idea to celebrate her b'day...Anyways, wishing your Her ( and you too ) a Happy time ahead.

Who is the person you are buying a gift for? Is it your mother? My mum's birthday is also on 16th December so I will probably make her a cake, buy her some flowers and some other small gift and, since I have already arranged to have the day off work, spend time with her. If it is your mum, making something yourself would probably be special to her. If its your wife/partner then you will know better than the rest of us what sort of thing she would like.