Billed as the new Thierry Henry, Mbappe made his top-flight debut for Monaco in December 2015 when still aged just 16.
"I always had lots of imagination when I was little, so I am not going to say that I hadn't imagined it," Mbappe told AFP in an interview when asked if he expected to have won a league title and become a full international at such a young age.
"I imagined succeeding early, but I didn't really think things would happen so quickly."
"Of course I always believed. The players who have succeeded in their careers are the ones who believed in themselves."
Billed as the new Thierry Henry, Mbappe made his top-flight debut for Monaco in December 2015 when still aged just 16, but it is in the last six months that he has gone from a player of great promise to one of the biggest stars in Europe.
He scored 15 goals to help Monaco win a first French title since 2000 and won his first cap for France in March.
He is now being linked to mega-money moves to one of the continent's biggest sides this close season, with Real Madrid leading the chase alongside the likes of Arsenal, Liverpool and both Manchester clubs.
On Tuesday he earned his fourth cap for Les Bleus, starring in a 3-2 friendly victory over England in front of almost 80,000 fans at the Stade de France
The following day he was speaking at the Edouard Rist clinic in Paris in his role as an ambassador for an association called "Lead Climbers" which backs sporting initiatives for hospitalised children.
Mbappe has taken on a lot of responsibility for one so young but he thrives on his new status, as his assured nature before the glare of the cameras attests.
But such self-confidence should not be mistaken for arrogance, he says.
"No, it is a strength. But having belief in yourself is not enough -- you also need to work hard and always respect the people around you."
"I think when you show respect to people, they respect you back. But it is important to be yourself."
"That is part of my personality. I have always been a chilled out kid who doesn't get carried away," added Mbappe, who hails from the often deprived northern suburbs of the French capital.
"My entourage has always helped make life easy for me and I never had any real difficulties growing up."
Mbappe was unlucky not to score his first international goal against England, hitting the bar in the second half before setting up the winner for his fellow young starlet Ousmane Dembele.
At times he had the Stade de France crowd gasping with his skill. He is already an idol for aspiring young footballers but he accepts being in the public eye and acting as a role model is a key part of his job.
"That is the business we are in. Everyone would love to be in our shoes," he said.
"I don't mind that people expect a lot from me. When I was a child I had idols and footballers are idols."
"You place them on such a pedestal that they can't do anything wrong. That is a challenge but it is also interesting, because it allows us to keep learning while also making sure we continue to serve as a good example to these young kids."