Congratulations! You can give her a creative gift, such as a crystal piano music box customized with photos. You can carve photos of your sister and your brother-in-law into the crystal. It is a very romantic gift. Not only is it creative, but your sister will also like it. You are still a college student and still in school, so you don’t have to buy gifts that are beyond your ability. You can’t let giving gifts become a burden. If you have time, you can also go out to do odd jobs, or buy a better gift for your sister.
No matter what the gift you give is, I think your sister will be very happy. This is your blessing, so she must be very happy. You can give her a handmade customized gift to express your blessings to her, such as handmade DIY blessing chocolate. This is a very creative gift. The blessing can be written on the chocolate, which represents the constant blessing.
If you have time, you can also make gifts for your sister by yourself. Such gifts are more thoughtful. Like handmade origami, handmade painting, etc.