I was 15 when I left Afghanistan. I still felt like a child, but I tried to act like an adult. The situation there was very difficult for me and my family; it’s a long story, but I left home because of the civil war and a family dispute. It took two months to get to France: walking, in cars and lorries, on a boat. We walked 15 hours through the mountains to cross the Iranian border into Turkey.

My 16th birthday came and went without me even realising. I was living in a tent in the refugee camp in Calais. I had a phone, but the connection was very bad and it was hard to charge it. On that day my family didn’t call. I didn’t celebrate my birthday much in Afghanistan, either: I’m one of seven children, and we faced problems from all sides; we didn’t think much about birthdays.

I was in Calais for seven months. For the first two, I spent most nights trying to get to the UK. I got on a lorry so many times, but every time I was taken off by the police; they hit my legs with truncheons. One time, I jumped from a lorry and broke my hand. It was very painful, but I didn’t go to hospital. I found a doctor in the camp who bandaged it. Then I met lawyers from the charity Safe Passage, who told me there was a legal way to join my sister in the UK. After that, I stopped trying to get on lorries and waited for a decision to be made.

In Afghanistan, I was a very fast runner; but after a year of travelling, I wasn’t fast at all

There was a school in the camp, but when you don’t feel relaxed, you can’t take in the words. I was very depressed, and hungry. At first, there was only one meal a day; later there were two, but you had to be quick to get breakfast. Usually, I didn’t sleep at night – there was no law, no police in the camp. It was the same as Afghanistan: very scary and violent. After I got to London, it took weeks to get used to sleeping in a normal, comfortable bed.

I arrived in London by train on 7 April – I remember looking out of the window when we came out of the Channel tunnel. My sister and brother-in-law met me at the station, and we took a taxi to their home. There were so many people, so many nationalities. The men looked the same as they do in Afghanistan; the girls looked different. In Afghanistan, you should cover your head and your body, but it’s different here.

Facebook Twitter Pinterest ‘After college, I go straight to the library to study, then I try to go to the gym.’

Now I’m studying at college, focusing on English and maths. My English is getting better, but sometimes I find it hard to understand British people. The school is much better than the ones in Afghanistan. In most of the schools I was at, the lessons weren’t good because of local government corruption; sometimes, I felt I was just wasting my time. Here, the teachers are nice. There are people from all over the world at the college – a few from Afghanistan, but most from eastern European countries.

I don’t go out much with them. After college, I go straight to the library to study, then I try to go to the gym. In Afghanistan, I was a very fast runner; but after a year of travelling, I wasn’t fast at all. At the gym, I’d get pain after running for just two minutes.

When I had days off school in Afghanistan, I’d play football and see friends, but my family wouldn’t let me go anywhere central, because there were so many Taliban attacks. It feels safe here. Sometimes, when I see the British police, I am reminded of the French and Afghan police, and feel scared, although I know they are different.

If I was a politician, I’d focus on trying to stop the conflicts in Syria and Afghanistan

On Saturdays, I play football or go to my auntie’s. My brother-in-law has a wholesale business. We live in a house and I have my own room. The rooms are smaller than in Afghanistan, but I like it. Two weeks ago, my sister had her first baby, a boy. I still miss my country and my old friends. Sometimes I feel lonely, because I don’t have my family, my mother and father.

I’d like to be a politician, an accountant or a web designer. A few weeks after I arrived, I was invited to talk about my experiences to MPs in the Houses of Parliament. There was no translator, so I had to speak English. Slowly, as I spoke, it got easier. Later, I spoke in front of 500 people at the National Theatre; it was the first time I’d spoken in front of so many people. That’s when I thought I’d like to be a politician. I want to serve the country I live in. I want to make myself here, to grow my talents, and go back to Afghanistan at some point. If I was a politician, I’d focus on trying to stop the conflicts in Syria and Afghanistan. The UK is a world power; they can do something. If there was peace there, people would not need to flee here. I don’t know if they would accept me as a politician in the UK, because I’m foreign, but that’s what I’d like to do.

Facebook Twitter Pinterest ‘I have a great opportunity here, but my worries are not over.’

I feel awful for the boys I was with in Calais: most of them are still in France and in a bad situation – some have been waiting for eight months, a year, two years. One boy arrived in Calais at the same time as me. After seven months, his hair began to turn grey from the stress.

I don’t think I’m a child and I don’t think I’m grown up; I feel in the middle. My sister, who is 26, treats me like her little brother; she cleans my bedroom and tries to take the place of my mother and father. In Afghanistan, people don’t have the same idea about teenagers. By the time you’re 15 or 16, you should know how to talk to guests. In the UK, they treat you more like a child. When I got here, my sister and brother-in-law told me I should behave, be polite and study hard. They said if people offered me alcohol, I should not accept it. It wouldn’t be right to find a girlfriend: if you want to be with someone, you should marry her.

I have a great opportunity here, but my worries are not over. I don’t know how long I will be able to stay. They gave me an ID card and I’m waiting for my visa; the Home Office the case is delayed. Maybe they will give me a visa to stay for ever, but perhaps they will send me back. It makes me feel depressed when I think about it.

• The Guardian’s Christmas appeal is supporting Safe Passage, a charity that helps child refugees like Omran find a legal route to the UK. Donate online at theguardian.com/charity-appeal-2016