"I haven't been to France before so it is something a bit different and obviously playing at the world cup is going to be pretty exciting so I am looking forward to that," he said.
"Ever since I was little, it has been a dream of mine with the ultimate goal to become an All Black. This is at my age the equivalent of being an All Black."
Mafileo finished his schooling at St Kentigern College before moving to live at Mount Maunganui as part of the Bay of Plenty Academy.
"I just can't wait to get out on that field and pull on that black jersey. It is just a New Zealand thing when you put on boots to be proud of who you are playing for, whether that is club or for school," he said.
"For myself it was a good move to move from Auckland not just for rugby but to look after myself and live with the other flat boys. It has been a good life-learning thing for me."
Trask says the support from Bay of Plenty Rugby has helped get him where he is.
"They have helped with what we need to work on. Bay rugby is in a good space at the moment and it is great to be part of it."
Trask and Mafileo were part of the New Zealand team that earlier this month defeated Australia to win the Oceania U20 Championship held on the Gold Coast.
The confidence from that final win, in particular, has given the squad coached by Craig Philpott a major confidence boost ahead of France, where they have Japan, Wales and Australia in their pool.
"It was pretty good to get the win against (Australia) but there were a few work-ons, a few structure things from our set-piece from that tournament and just moving on to the world cup," Mafileo said.
There may be a surprise or two for close watchers of the haka to be performed by the New Zealand U20 team.
"We have put our own little twist on it. We have our own different actions. You get a lot of energy from it and a lot of pride. It just reminds you of where you are from," Trask said.
New Zealand Under 20 schedule
New Zealand v Japan
Thursday, May 31, 7am (NZT)
New Zealand v Wales
Monday, June 4, 2.30am (NZT)
New Zealand v Australia
Friday, June 8, 7am (NZT)
Matches will be broadcast live on TVNZ Duke and streamed live on tvnz.co.nz