Since you are both cadres in the school, it means that you are both excellent people. It may not be appropriate to express your affection to your senior sister directly. It is better to express your meaning through gifts. Save some of these.
1. Crystal represents pure love. It is perfect to give a senior sister a crystal ornament. As for the pattern, you can choose a peach heart or rose pattern, or you can DIY and customize the words you want to say to her. There is also a light base under this ornament, which can glow at night. If she accepts your gift, it proves that she accepts you.
2. If you want to express your feelings to your senior sister, you can give her a rose-shaped cushion. Such a gift can represent that you have a good impression of her. If it is rejected, it is also an ordinary gift. It can be said that you are giving her a cushion as a junior.
You can buy two movie tickets for the love blockbuster that was recently released in the cinema and ask her if she has time to go to the movie together. If she answers, it proves that she accepts you. If she says she is busy and can't go, then everyone will not hurt face.