The young Brit was quickly promoted to Formula 1 when McLaren decided to axe Stoffel Vandoorne after two seasons with the team.
Norris' promotion happened due to his highly successful junior career, winning three championships in 2016 and then became Formula 3 champion in 2017. He then finished as runner up to eventual Williams driver George Russell in Formula 2.
Speaking to RaceFans, Norris said that he only at the point when his seat was confirmed that he thought he would get to race in F1.
“It was always my ambition, since I was 13 or 14. I always wanted to but I [did] not always believe that I could do.
“I knew I was reasonably good and I won races and some championships but it’s still not a guarantee you’re going to be in F1.
“I never believed I could get to F1 until I was told I was going to have the seat,” he added. “I don’t know why, I just never believed it. Before I got told, no, after, it was a yes.”
He also admitted that he had surprised himself with his performances this season, at least in comparison to his teammate Carlos Sainz.
“I’m not surprised I have the ability because I’ve been good in other categories which has given me some confidence. But F1 is completely different and I didn’t know how I was going to do against Carlos, how I was going to do against all these other drivers who are the best drivers in the world.
“I don’t think I’ve done amazingly, I’ve done pretty well, but I still [didn’t] think I would have done as well as I have done in terms of my competitiveness in general.
“Obviously compared to Carlos as a guy I can compare with, but not just against him. Racing other drivers, drivers who’ve been in F1 for many more years than me, people with a lot more experience, people in faster cars and so on. I’ve done things which I didn’t necessarily think I would one hundred percent be able to do.”
Bahrain International Circuit - Winter testing