Protip: shoot embarrassment in the face and bury it in a ditch, you're in the entertainment industry and bound to run into shameful acts you must perform.
It looks less like embarassment and more like guilt — she's at least in her 20s, and judging by the references she drops, the "17-year-old" Nana is probably around 35.
This is because you're helping me all the time, Nana-chan~Th-Thank you very much..Miyu-san gave Usamin a new year's allowance. Traditionally, only given to children.