You are a very thoughtful boyfriend. I believe your girlfriend will be very happy. Birthdays are a big deal for every girl. Not only will they receive many birthday gifts and blessings on this day, but more importantly, as birthdays continue, their years are gradually fading away. So every birthday should be spent with great care. Since you want to spend it romantically, I can give you a few small plans:
1. Rent a boat and take her to the middle of the sea to spend an unforgettable birthday. Prepare cakes and gifts, and of course fireworks. I believe this way will definitely make your girlfriend feel very romantic.
2. Take her out of town. I suggest going to Hong Kong Disneyland. Every girl has a princess dream in her heart. Disneyland is exactly such a dream. I believe such a birthday is romantic enough.
3. You can also take her to plant a tree as a commemoration of her birthday, and of course it is also a commemoration of your love. This is also a very romantic way to spend a birthday.