Malala tweets a photo of her first day at Oxford

On top of being the world's youngest Nobel Peace Prize winner, Malala is also a pretty darn good student and the A-grader started her studies at Oxford yesterday.

She tweeted a picture of her first day of uni and remembered how far she's come.

Also read: Malala asked for packing tips for Oxford. How did Twitter respond?

But trust younger brothers to butt into sombre, pensive moments.

Khushal Yousufzai responded to Malala's tweet, saying that he's happy she's still around and he's pretty sure he'll join her at Oxford in a couple of years.

But Malala was having none of it!

And Khushal had to bow out of the debate.

Looks like Malala really knows how to play her big sister card!

Malala is studying for the PPE degree (Politics, Philosophy and Economics) at Oxford.