Having already set new records at the recent Auckland Track Challenge and without much competition, the pressure is off the 20-year-old.
The Aucklander is just hoping to enjoy herself, before she heads to Europe for some more serious competition later in the year.
"Nationals are always a good one, because we get a good crowd," McCartney told herald.co.nz.
"The stadium is really nice. It has got nice big, green banks everywhere and it is a really nice place to compete, I always think."
For a pole vaulter, crowd encouragement really does lift an athlete to higher marks.
"It really does make a difference," McCartney explained. "It just creates an atmosphere, and when you get an atmosphere, you get more adrenaline, you get excited and people are clapping you and wanting you to do well.
"It certainly changes the mood a little bit."
Having jumped 4.82m in Auckland three weeks ago, many wonder just how high she can take the New Zealand and Oceania record, but that doesn't seem to have any impact on her preparation.
"I try to have the height as almost the secondary goal," she said. "It is not my main focus.
"I usually have a couple of other things that I want to work on, so going into the Auckland Track Challenge, I was thinking about doing every run properly. I didn't want to run through at all and that actually went really well."
McCartney is operating off a shorter run-up at the moment, but will extend that when she heads off to Diamond League meetings and builds up to the World Championships in London later this year.
So what height does she think is possible?
"It is going to be interesting to see how it goes," she said. "As long as everything goes well and I go off to Europe healthy, then I have some big competitions over there and big people to compete against, so that should hopefully bring out some big heights and we can see what is possible.
"I'm too scared to put a number on it - I'd rather sit back and just see how I go."
McCartney is quick to point out that, while she competes individually, it is her work with coach Jeremy McColl that leads to success and that indeed is very much a partnership.
McColl and McCartney have worked hard since Rio to make further gains.
"There have been a few things I have been focusing on. I still have strength to gain and speed to gain, and technique is something I'm always working on.
"Since Rio, we have really tried to nail my run-ups, because that has been a little bit of a funny thing in the past. If I nail a run-up and I'm confident on it, then usually I am going to jump higher.
"That has been our big thing over the last few months - getting the running mechanics right, so I then feel very comfortable in the run-up."
Herald.co.nz will carry live streaming of the national track and field championships from 9am Saturday and Sunday.
