Barbados-born Archer, who is eligible for national selection under new England and Wales Cricket Board residency rules, said he was surprised by his quick elevation.
"I thought I would have to wait a couple more years before I would be in contention for the full squad, I thought I would have to play for (England) Lions," the all-rounder, currently playing for Rajasthan Royals in the Indian Premier League, told reporters.
"I was fully prepared in my mind that it was going to be a seven-year job. When I found out I was qualified more quickly it was obviously a bit of a shock but also exciting."
While the 24-year-old has admirers in England regulars Ben Stokes and Jos Buttler, Chris Woakes said it would be unfair for England selectors to ask any player to make way for the uncapped Archer.
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"I understand the situation and I'm very happy with everything. I don't want to step on anyone's toes," said Archer, whose ability to bowl at more than 90 miles per hour and power-hitting make him a limited-overs asset.
"I'm not in the World Cup squad but it's a great chance for me to show what I can do and anything can happen. If someone gets injured, I want to put myself in a position where I'm the first person they turn to.
"I'm going to give it my best shot. I've worked pretty much all my life for this moment and I just want to tackle it and put my best foot forward."
Even if he is not eventually picked in the final World Cup squad, the 24-year-old said it was not going to be the end of the world.
"Of course I want to play in the World Cup, but if it doesn't happen for me I'm not going to get upset."
England play Ireland in a one-day international on May 3 before a five-match ODI series and a Twenty20 against Pakistan. The World Cup begins on May 30.
(Reporting by Rohith Nair in Bengaluru; Editing by Amlan Chakraborty)
