Step daughter birthday

Well my boyfriend daughter , we are not married. What should I do for her birthday? I have been with him 2 years , she’s turning 9 & we have a pretty good relationship.. Improvement is needed but overall it’s great , she’s sweet to me , sometimes have a little attitude that hurts my feelings which is rarely like maybe twice in 2 years. He usually just buy them gifts for they birthday and once they come over give it to them. She’s the only girl ... ( I don’t have kids ) .. She will be at our place the day of her birthday actually. . . We both usually just buy gifts separately for each kid birthday and then give it to them .. wanted to do something different maybe?