Why would sarah be surprised that Adnan made sure Jay got a gift for her serial season 1

Sarah was surprised that Adnan had asked to Jay for getting a gift, because it was rather natural that the boyfriend of Stephanie (who was Jay) would give her a gift on her birthday, but if someone else, such as Adnan was wasn't her boyfriend would suggest Jay (actual boyfriend) to buy her a gift that it wasn't a normal. Sarah might have not known about the close friendship of Adnan and Stephanie so this might had put her in surprise