I don't wanna have a go at individual players of such an age but surely the alarm bells should be ringing at this stage for NZ - this year at age group world cups we have been outplayed by Mexico, Colombia, Chile and now Nigeria. All teams that are ranked well behind us in the womens rankings. I'd suggest it's a sign of things to come in the senior space as more and more nations start taking womens football more and more seriously.
We were shown up partly because the confederations such as Africa and South America that previously weren't very strong in women's football have been making big strides and are now producing more sides that are competitive.
But the major factor is that this was a NZ side which assembled a week before the tournament started, having played no qualifiers and no friendlies.
They played the one international friendly against Canada in the week before the tournament.
They were playing sides that had been together for several months and had come through tough qualifying tournaments and played many friendlies.
Chile had their South American qualifying tournament in April but had played in two friendly u-17 international tournaments since then:
https://anfp.cl/noticia/37406/la-preparacion-de-la-roja-femenina-sub-17-para-el-mundial-tuvo-un-provechoso-capitulo-en-mexico
In italy against Italy, Mexico and India.
And against Mexico, Canada and Colombia in Mexico in September.
Nigeria played six CAF qualifying matches in three rounds, home and away, between March and June.
Before the World Cup they had a camp in Turkey where they played Galatasaray's and Fenerbahce's women's teams.
Germany came through both qualifiers in March for the UEFA u-17 finals (three games) and the Finals (five games) in May. Plus friendlies before and after those events.
AFC qualifying was also cancelled and China, unable to play any friendlies due to their country' strict lockdown policies struggled like NZ, finishing bottom of their group in India.
Japan (quarter-finalists in India) by contrast played numerous friendlies this year, including three in France in August (two against France u-17 and one against a French women's top flight side):
https://en.wikipedia.org/wiki/Japan_women%27s_national_under-17_football_team#Results_and_fixtures
Canada and France also failed to win any matches in India, so perhaps we shouldn't feel too bad!