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