Read the text and answer the question.When I was a little boy, I wanted to be a pilot. I thought it would be so cool to fly an aeroplane around the world. But my dream changed when I got a bit older and started playing football. Then I wanted to be a professional footballer.I played for my school team and I played for my local team at weekends. I was really good and when I was 14 a scout from Manchester United came to watch me play. They offered me a place in their youth academy and I moved to Manchester with my dad. I loved it there! The training was hard but I was playing with some of the best young players in the country. I played for the England Under-16 team, the Under-17s and the Under-18s. And then, when I was 18, I made my first appearance for the Manchester United First Team. It was amazing!But after that, things didn't go so well. I got injured and I couldn't play for a long time. I had to have an operation on my knee and I had lots of physiotherapy. When I was better, I went back to training but I wasn't as good as before. There were so many other good players at the club and the manager told me I wasn't going to get many more chances to play for the First Team. I was really disappointed and I left the club.Now I'm not sure what I want to do. I like cooking, so maybe I'll be a chef. Or maybe I'll go to university and study sports science. But one thing's for sure - I'll always love football!Why did the narrator leave Manchester United?