"It's definitely one of the toughest groups, the group with the USA is probably the toughest followed by ours," Readings said.
"We're the lowest-ranked team in our group against three teams that we know pretty well.
"We've played against China quite a lot recently and Holland we've played many a time in Cyprus and Canada we know well, we played them just before the Olympics.
"We know each game is going to be tough, there was never going to be an easy game at the World Cup. I think with our group that's even more so. But they are three games we're going to be looking to win because we've got ambitions to go all the way in this tournament and at least now we know the three teams so we can begin our preparation work for them."
The second match of the tournament in Edmonton sees the team get together again with former coach Herdman and Readings says the group will be dialled in for what will be a great occasion.
"It will be a really good test and both teams have got players who have been in their teams for a while so the players know a lot about each other, so it will be a real battle on the pitch.
"It will be a real good challenge for us in the tournament and it will be a great occasion because we'll get to play in front of a lot of fans, which we're used to.
"We've played against the hosts quite a few times now; in the 2007 World Cup and also the Olympics last year, so it's something we're used to and it's something we relish and we're looking to take that challenge head on."
The Football Ferns have won three of the last four meetings with China, including a 4-0 win over the Asian nation at the 2013 Valais Cup in Switzerland, while Canada won their last match with the Ferns 2-0 in the lead-up to the London Olympics.
New Zealand's last encounter against the Netherlands was at the 2012 Cyprus Cup where they drew 2-2, before losing on penalties.
Fifa Women's World Cup 2015 - draw
Group A (rankings)
Canada (8th)
China (14th)
Netherlands (15th)
New Zealand (19th)
New Zealand matches (NZ time)
Sunday, June 7
New Zealand v Holland
Commonwealth Stadium, Edmonton
Friday, June 12
New Zealand v Canada
Commonwealth Stadium, Edmonton
Tuesday, June 16
New Zealand v China
Winnipeg Stadium, Winnipeg.