He was five, it was his very first taste of football and he'd scored an own-goal.
"I cried and went home, I wasn't really good at all."
Nypan is either an incredibly harsh self critic or just improved at a remarkable rate, for just a decade later he was making his first team debut for Rosenborg.
When, then, did this teenager, described as a "generational talent", realise that he was maybe a bit different to other kids his age?
"I don't know, it's difficult to say," he tells the Northern Echo in a sit-down interview at Middlesbrough's Rockliffe training complex.
"I really have always had that drive to be good, to be the best in something. It doesn't matter what we're doing, I want to be the best in that thing.
"My friends, where I came from, it was always just football. Everybody was playing football. I was really lucky to be growing up in the area. We were playing football every day at school and every day after school, so I became better and better and by the age of eight or nine, I was pretty good.
"From when I was seven or eight, I just had this dream to become a footballer when I got older. You always have that drive and in time you get closer to the goal, so I wasn't so much thinking about the goal but just enjoying the road."
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And, there, immediately, we get a glimpse of the maturity that has no doubt aided Nypan on his rapid climb and helped to ensure his feet remained rooted firmly to the ground despite the knowledge that scouts from some of Europe's biggest clubs were watching very, very closely after his Rosenborg breakthrough. The likes of Arsenal, PSG and Manchester United were all linked before Nypan eventually moved to Manchester City this summer for £12m.
"It was actually quite difficult at times [to handle the high profile speculation], but also really cool, I'm not going to lie," he says.
"That's something you want, for people to be interested. That means you're doing things well, so I think it's both good and sometimes bad.
"When you don't perform or you have an injury and stuff it is hard because you want to be playing well, but you can't sometimes, and that's that's difficult. And especially when you're a young age and people expect a lot from you when Manchester City wants you, you have to play like a star. It's really cool when it goes good.
"You get used to the attention, it's part of the package of being a footballer.
"Sometimes it's hard, especially when you don't perform, because you know that people expect bigger things from you and 16, 17, 18 year olds aren't going to play good every game or every training session. But you just have to be strong."
Despite the high-profile transfer interest in recent seasons, Nypan was in no rush to leave Rosenborg. He had plenty of opportunities to move before heading for the Etihad this summer, but the midfielder, his family and his representatives never shifted their glare from the bigger picture.
"I was maybe 16 when it all started to blow up," he says.
"I started to play regularly. And I was in a really nice place, really good team and I got playing time. I started to get to be one of the players that have to perform in the team and that was really good for my development.
"I was in no rush to leave. Obviously it's tempting when big clubs want you at an early age, but I think it's really important to just be calm and remember your time is going to come and don't rush anything.
"If you're in a good place and you play regularly and the opponents are what you need, then there's no point in changing and that was something my agent and my father was really stressed."
Which leads us to Middlesbrough. Nypan knew a loan was always on the cards this summer and a move to "big club" Boro made perfect sense. He loved his first phone chat with Rob Edwards, liked the style of play and liked the idea of regular football in the Championship as he adjusted to life in England.
This is all new to Nypan, who moved out of the family home for the first time this summer.
He is teaching himself to cook - "I'm not that bad" - and plans to get out and about in the area. But life for Nypan is geared towards performing on the pitch. On evenings, he focuses on recovery.
"I'm waiting for EA 26, but I'm also a movie guy," he says.
"I'm adapting to the new culture, though, and the new environment. It's a lot of new things and you learn so much by moving. It's really good."
Nypan's story has drawn inevitable comparisons with Martin Ødegaard, and while Boro's midfielder says the pair are "quite the opposite" in terms of players, he knows he can learn from the Arsenal captain.
"I won't sit there and say that it's not a nice comparison because I take it, it's an honour to be compared to a great player like that," said Nypan.
"He's maybe the best ever from Norway. So it's great to get the comparison, but we are not the same player. For me, we're quite opposite. We are maybe the similar type of area in the midfield, but the playing style is different. I won't grow up to be a Martin Odegaard, that's for sure.
"I remember when he came through, it was around 2015, and I was a young player. He obviously became a role model for a lot of Norwegians at that time.
"And you can also see that he didn't go straight in to the Arsenal team like he is now. He had some ups and downs. You see that even a player of that quality has some ups and downs, so that's nice to see. You just have to learn from everyone."
Nypan made his Boro debut from the bench at Norwich and then made an impact from the bench against Sheffield United, involved in the build-up to Tommy Conway's winner.
He played as a No.10, but is equally as comfortable slightly further back as a No.8
"I can play both, I don't want to say which one is better," he said.
"You just have to change a little bit of the mentality. You have to be a little bit more safe on the number eight and number 10 you can maybe try something more difficult.
"But I enjoy playing both. As long as I'm in the middle of the pitch, I feel like I'm where I'm supposed to be.
"I like to be in the middle of the field. I like to be on the ball and I like to create. Yeah, just give me the ball, that's what I want. But I can also help out in defence, I know you have to be in both boxes.
"I was really ready for this move and I'm enjoying life right now.
"I'll keep going with my development here, that's the plan. And hopefully help the team as much as I can as a Boro player. My goal is to help this team fight for promotion."