For the special lady in your life it has to be the special and perfect birthday gift.
A few great gifts  ideas:
Jewelry
Every girl loves jewelry. So it draws a conclusion you should buy her a necklace or ring for her birthday, try to purchase a piece that has some special meaning to your relationship. Consider buying a mother necklace or pin with an additional child charm, if you have children, or bead for each child you have. Another thought, if you don’t have kids, think of a special moment the two of you shared and purchase a charm or necklace along those lines. For instance, if your first date was at the circus, zoo and so on, it may be useful to select an appropriate charm.
Take Her on a Trip
Sometimes going on a trip can be much better than any present you could ever purchase. A trip can be exhaustive as leaving the country, trip to a city nearby. Try to get out of town, to some beautiful place like countryside, and it can be a wonderful stress relief and can show her how much you care.
Depending on the lady you may need to let her know in advance where and when you plan to take her on this out of town adventure. Consider packing her a bag and surprising her with the trip. This surprise can bring her a great pleasure and surprise of the moment a lot to the thoughtfulness of the trip.
Re-create your first date
Deep down all women are hopeless romantics and it goes without saying. Make her sure that you remember your first chance encounter by recreating your first date. She is able to appreciate it. Try to recreate the date with as many details as you can remember. Did you relax outside on an old striped blanket? So, find the same blanket.  If you are going to go to restaurant or to some bar-room, book the exact same dishes. Little details can mean a lot.
Pamper Her
Every woman can appreciate the opportunity to relax, and if you have the money, send your special lady to a spa for the weekend. . If you’re working on a budget, give her a weekend spa trip, in your own home. It’s possible to do it in such way: cook her dinner, clean up and offer to give her a massage. You can even get some candles and body lotions in one of the local stores to add to the effect.