Hey, sounds like a nice fella and great that things are going well!

Present.. what have you learned about him so far? What does he like to do? Does he like movies? Buy him a gift card. What about an making a paper invitation for a picnic date, or something light hearted an fun? Can you bake? Perhaps make him a lovely cake for his b'day? Take it around with some helium filled balloons - it looks fab, and shows some effort. Nothing has to be big or grand, esp as its the first b'day between you. Enjoy tomorrow night :-)