You are a very thoughtful boyfriend. I have seen very few boys who can make gifts for their girlfriends. But for birthday gifts, whether it is handmade or not, as long as you give it with your heart, it will be enough to make your girlfriend's heart move. So I can give you some special suggestions, I hope it can help you:
1. If you plan to make it yourself, I suggest you go to a pottery museum and make a pottery for her. It may not be so easy to make, but only in this way will it feel meaningful. Such a birthday gift will definitely be very popular with your girlfriend.
2. You can also make a birthday cake for her by yourself. There are those cake DIY shops. You can make your favorite patterns or words on her birthday cake by yourself. It is a very romantic birthday gift.
3. You can also go to a jade shop, choose some beautiful jade for her, and put it on her by yourself. The birthday gift with your own heart will accompany her for a long time.