Esteban Gutierrez believes it is too early to say if he is ready to compete in Formula 1 after securing a Sauber race seat for 2013.
The 21-year-old Mexican graduates from GP2 having been Sauber's reserve for two years and driven in Indian Grand Prix practice when Sergio Perez was unwell.
Gutierrez admits only time will tell if he is ready for the highest level.
"To be honest I don't know if I am ready yet," said Gutierrez. "When I'm in the position of being an F1 driver next season then I will know if I am ready or not.
"Definitely I feel that I was comfortable to do the next step in my career. After all the experience in FBMW and F3, GP3, two years in GP2, and now F1, it is one of the basic introductions to racing.
"Now reaching F1 is just the beginning of a reality so I am pleased for it."
He added: "It doesn't make sense to say I am 100 per cent ready; it is difficult to say or judge right now how ready I am.
"I am doing my best and using all the time I have on track to improve my knowledge of the car, not only the driving itself but also the feedback to the team as I know it is a key factor in F1. It will be an interesting experience to go and have the right input into next season."
Gutierrez said he had no expectation of instantly matching predecessor Perez's podium-grabbing form.
"It is important to take it in a very realistic way," he said. "Of course I am going to try to adapt as quick as possible and not only as quick as possible, I want to reach a certain solidness in F1.
The Mexican says his main priority for his rookie season will be to reach the consistency he lacked in GP2.
"I am totally aware that competition in F1 is not easy, it is the top level of the sport. Living what I lived in GP2, it is true that I didn't reach a consistency, but I rate it as the most rewarding season of my career, because to have this experience gives you new perspective into what you can influence in the future.
"So I will look for consistency in F1, then after reaching this consistency we want to look at the top results but first of all it has to be step by step - and adapting at the beginning will be very important."