Manchester: On Tuesday morning, Katrina woke up shaking.

The memory of the blast, the screaming, the smell of smoke – the frantic search for her mother after the Ariana Grande concert was hit by a suicide bomber – came back to her all at once.

The 16-year-old cried.

Then she got dressed, went to school and sat an exam. And that evening she was in Manchester's town square at a vigil to express her thanks to the city's police and emergency workers, and her solidarity with the rest of her home town.

"She is a strong girl," said her mother, Jana Matulono.

Standing proudly in the square, holding a single white rose, Katrina told her story, calmly at first, then a little more carefully, strong emotions in check, as she remembered the horror of the previous night.

She was on the right side of the stage, very close to it. The explosion happened opposite her in the foyer, just after the concert's end.

At first she thought it was a big balloon from the show popping, but it was too loud. The word spread through the crowd that it was a bomb.

"That was terrifying because everyone was screaming and shouting, it was really scary," she said.

Katrina realised "I'm getting targeted by someone who wants to hurt me and all these other people who are children," she said.

She looked at the crush of panicking people running for the exits, and at first stayed where she was.

"The stairs were so narrow and very steep that children were falling and people were stamping on each other," she said.

Once she got out into the foyer, the exits were blocked.

"That was the scariest part because that's when you thought 'I'm getting attacked and I'm actually in danger'," Katrina said.

She finally found her way to the pre-arranged spot where she was to be picked up.

"My phone died and I was alone," she said. "I was waiting for my mum and her boyfriend David to come and pick me up. As we sat at the meeting place near the arena, that was a little bit scary because (police) were telling me to go away and evacuate the area but I still couldn't find my mum until she came, screaming my name."

Ms Matulono said she had been on her way to pick up Katrina when her phone lit up with messages from friends, telling her about the attack.

She reached the arena gates, jumped from the car and ran.

"I just saw young girls crying, so upset," she said. "I didn't really understand at that moment what had happened."

Police wouldn't let her near the arena.

"I was just shouting 'I need to go in, my daughter is in there'. I didn't care what people were saying."

Then, in a stroke of extraordinary luck, "I saw her. She just ran in front of me. She said 'mum, mum'. She called to me."

They embraced, and turned to jelly.

"Katrina, she was white, looking like a piece of paper. She said 'I can run now'."

So they did.

It took to the next morning for Katrina to realise the extent of what happened – and to hear the number of dead. She thought "that could have been me".

But she went to school, and sat an exam.

"At first I was very reluctant to go because I was still so scared. When I woke up I was still shaking.

"But I thought it would be much better to go and to prove it's just a normal day."

And she went to the vigil at Manchester Town Hall on Tuesday night – with her mum.

"I think this just shows how people actually care," she said of the vigil. "That attack was just one person. It's much better that there are so many other people, showing we are much stronger together."