My sisters birthday is next week. (18)

It’s my 18 year old sisters birthday next week. So I have been just brainstorming ideas to surprise her with. It’s already an issue with my parents work schedules. My parents never attend family events. They are too busy to make time. So we have to plan around their work schedules. My sister and I are hoping for a sweet dinner in the house, maybe some cake. I thought about getting her a card, and just writing some words to her. I know she doesn’t like flowers. She has already said no to a shopping trip.