Why does Moana say 'I've delivered us to where we are'?

"Where we are" is not focusing on the geographical location of the speaker, but rather the state of the world (= her people). Moana has changed her world, and she's acknowledging that fact when she says "I have delivered us where we are".

It's the equivalent of saying "I made the world the way it is today".

To further extend this, I found the following sidenote on Genius:

Here the wayfinder from “We Know the Way” is seen sailing past Moana and is seen to recognise her as a way finder herself. She has found her people’s ancient identity and her own and now they have affirmed it.

This is a big moment in the film as it’s the passing of the torch from 1000 years ago. The chiefs used to be people who kept their fleets safe and widened their people knowledge however Moana’s father has kept their people safe poorly by restricting their knowledge. Moana has learnt the ways of the past now and can take her people back to them.

Because Moana is the only one in Motunui that believes in grandma that insisted the legends are true.

...

Grandma: But one day, the heart will be found. By someone who will journey beyond our reef, find M?ui, deliver him across the great ocean to restore Te Fiti's heart and save us all.

Well, grandma clearly knows Moana has the potential judged by her personality (curious about sailing and the ocean as she was the only one got really interested by the story of legend among the other kids). Thus the ocean chose Moana as the chosen one to save the world therefore grandma decided to tell her the truth: who are we meant to be? The answer is voyagers. And Moana herself understands, once she restored Te Fiti's heart, the world would goes peace and their people could voyage again in which indicates she "delivered" their people back on the ocean to voyage where they're supposed to.

^{Disclaimer: These are my thoughts which it does make sense.}