She is an unlikely-looking soldier - slim, blonde and just an inch or two over five feet tall. For most girls her age, you'd like to think their biggest worry would be finding something new to wear for the weekend.
But Lance Corporal Mandy Rendall celebrated her 20th birthday at Basra Air Station in Iraq during four months of particularly heavy rocket and mortar bombardment.
"When I was there from January 22 to May 21, 2007, there were 301 rockets and mortars," says the former Peterhead Academy pupil, holding out an illustrated map for that time which is covered in fiery, orange explosion symbols.
"You always had to have your body armour and helmet with you. The second month was really bad for mortars. We had one that went right through our tent and it was `everybody helmets on and run'."
In those four months, 19 British soldiers died, according to Ministry of Defence figures.
A year later, with her 21st celebrations barely over, Mandy began a seven- month stint at Camp Bastion, the vast British base in the middle of the desert in southern Afghanistan.
Today, casually dressed in pale jeans and T-shirt, she's recounting her personal military history in the kitchen of the family home in Aberdeenshire. It's just weeks since she retired from the army after a seven-year career and it's extraordinary to think she's only 23.
Her younger brother Darren, 16, comes into the kitchen after a run: he's working on his fitness so he can join the army later this year. But Mandy's now looking for what she describes as a normal job, after leaving school even younger to join up.
Mandy first started thinking about an army career as a young teen at Peterhead Academy, she says: "Looking at stuff during school about the different things you can do, nothing flicked my switch. But looking at the army, it seemed fun, it seemed adventurous and totally different. It also seemed like you could see a lot, do a lot and get a lot out of it."
At school, PE teachers encouraged her fitness programme: "I took Standard grade PE, so we had it three times a week and I absolutely loved it. I love fitness, which is why a big part of me wanted to join the army."
After leaving school at 15, Mandy sat her BARB (British Army Recruit Battery) test, a series of aptitude tests which help match recruits to a suitable role. She was recommended to join the Adjutant General's Corps, which provides personnel and administrative back-up to the army.
"I've always been shy, especially when I was little. I wouldn't talk to anyone, even if they spoke to me - I'd have my head down. The army made me confident; it's done so much for me."
With a few months to fill before she could begin training at 16, Mandy headed for a preparatory Entry to Uniformed Services Course at Banff and Buchan College in Fraserburgh. "The course was fantastic because it was doing fitness every day and hill-walking, and they were teaching us about army life - about the airforce and the navy too, because it was tri- service," she says.
"One of the instructors, Linda Murray, was brilliant because she had been in the army herself. She used to tell us about jobs and little things, like the phonetic alphabet, so we knew that when we joined. It was an excellent course because it gave you good insight into what you wanted to do."
Days after her 16th birthday, Mandy started serious training following an exhausting train journey to the Army Training Regiment at Bassingbourn in Cambridgeshire. "It was drill, rifle lessons, a lot of PT and marching, and going out on exercises. To be honest, there were a few times - I think twice - I wanted to quit; I didn't want to do it any more. But I did keep going and it was good fun.
"Because you're not with your family, it's like you have all these new friends and they become your new family. So you rely on them, you talk to them and if anyone has problems, you help them out and you push each other to do it. The more weeks you do, the less you want to quit, because you think you've come this far, it's stupid to stop now."
Her first posting was to Germany in November 2003, but it wasn't all press-ups and early-morning runs. "I loved it, it was really good. They used to have cocktail bars and the summers were magic and they had outdoor pools and you could drive to Amsterdam for the weekend. Those years between 16 and 19 were absolutely wonderful for me."
Mandy was sent to Iraq twice - for a month in 2005 when she was 18, and then four-and-a-half months again two years later, working with the Joint Helicopter Force. Then in 2008, she was with the medics in Afghanistan, organising troop flights.
"I'll definitely miss it, I'll miss the people," says Mandy. "I had so much experience, so many laughs and met so many people I am still in touch with. You do a certain amount of time and then think: `I don't want to do it any more.'"
She's looking forward to her wedding to another former soldier: "I'd like a normal office job," she smiles.
Ten miles away, back at Banff and Buchan, another teenage girl is preparing to join the Royal Navy. Angelica Thompson, 19, finished S6 at Fraserburgh Academy last year and is taking the Certificate for Entry to the Uniformed Services Level 2.
Angelica is in her running gear, trying to shave a few seconds off the one-and-a-half-mile run women must complete in under 14 minutes to get into the navy.
"I want to be a Warfare Officer. It's when you take charge of the ship, when you navigate, making sure everybody knows where they are going, how to do chart work, look after weapons, give commands and ensure everyone does their job properly."
A powerful-looking 6ft 2in, she's had the navy in her sights since she was in primary. "I've wanted to travel the world and meet new people. I joined the Sea Cadets when I was 13," says Angelica.
She's doing this course to improve her running time and her knowledge of current affairs. "I need that to pass the entry tests. It is physical, but it's fun as I like being hands-on and don't like sitting in the classroom."
Angelica stayed on at school to do Highers in PE and maths and is studying Higher English this year to help her get naval entry as an officer.
Mandy's former tutor Linda Murray has taught on this course since it was launched nine years ago. Linda served in the Women's Royal Army Corps after leaving Peterhead Academy, then in the Territorial Army and as an instructor in the Army Cadets.
This course at Level 1 and Level 2 prepares students for entry to the range of uniformed services, including the police, prison and fire service alongside the armed forces. Most students are between 15 and 18 and study team-work and problem-solving, self-discipline and development, competitive sports, fitness and well-being, and current affairs.
"The most important unit is investigating employment opportunities in the uniformed services. And they investigate all uniformed services so they can make an informed decision," Linda says.
Students are encouraged to read newspapers and discuss events affecting the uniformed services and the armed forces: "They look at issues in the police service and where the army is serving and what the conflict issues are in Afghanistan or Iraq. So they know there is a possibility they would go out there and what the job role would be," Linda explains over a coffee break at the college canteen.
They learn why discipline is important and why they need to obey orders, but they also learn about their rights and how to deal with problems. "We teach them that what we class as bullying is not tolerated."
They are also encouraged to be aware of soldiers dying in conflict: "It's so they know exactly what they are going in for, so they're not thinking `Oh, that will never happen to me.' They may decide this is definitely what I want to do. But we also say to them that coming on the course and not joining the service is nothing to be ashamed of. You've just decided you're not wasting one or two years of your life and you're not wasting Government money by getting in and then quitting."
She says the role of women in the services has evolved since she started training: "Women are doing more and more active roles within the military. There are only a few that are not open to them, like the infantry, and some in artillery. But we can do an awful lot more."
Teenagers need parental consent to join the armed services before they are 18 and Linda says parents have mixed reactions.
"As a parent, I can understand that. Some of them are supportive. Some of them have said to me that their children doing this course has helped them, because it's relieved their minds that the kids are not going there not knowing what to expect."