What kind of things is she into, what are her hobbies her interests, what does she aspire to, what are her frivolous spends?
I buy fabulous presents, but I need more info on your sis......
Oh but I love to shop, moreso if it aint my money.
Also where are you UK or States? Need to know if I'm googling gifts.
And one more thing, altho it should have been the first. You sound like the sweetest, loveliest little sister ever mashallah. Long may your love and admiration for your sister last and I hope she too continues to love you so much ......I hope my girls are like this as they grow inshallah.