Activist Malala Yousafzai has thanked people for welcoming her to Twitter, and joked she is glad she waited until after finishing exams to join the social network.
The teenager, who campaigns for the rights of girls around the world, gained half a million followers in one day.
The Nobel Peace Prize winner, who moved to Birmingham after being shot in the head by the Taliban in Pakistan, finished school on Friday.
The 19-year-old has vowed to continue her fight for girls across the globe to receive an education.
She tweeted: "Graduating from secondary school (high school) is bittersweet for me. I'm excited about my future, but I know that millions of girls around the world are out of school and may never get the opportunity to complete their education.
"Next week, I will be back on my #GirlPowerTrip to meet girls in Middle East, Africa & Latin America.
"Each girl's story is unique — and girls' voices are our most powerful weapons in the fight for education and equality.
"On and off Twitter, I'm fighting for girls — will you join me?"
Her posts have been retweeted and liked thousands of times, prompting her to write on Saturday: "Thank you to everyone for the warm welcome. I'm still reading all your replies and it may take awhile. Glad I joined AFTER exams!"
Ms Yousafzai narrowly avoided death in 2012 after being shot on a school bus by the terror group for her outspoken campaigning over girls' rights to an education.
She was awarded the Nobel Peace Prize two years later and has continued to campaign for children's rights to education across the world, addressing the United Nations on the issue.