I agree with you! At the begining of the manga, she's really nervous and not very confident, but then because of all the things she goes through in taking on this male persona, we see her get more confident: she can't wait for someone to help her out when she's in trouble, she's got to try and help herself out first.
Maybe it's stretching things a bit much to say this, but it's sort of like the manga is commenting a bit on the artificial nature of gender roles: Nono slowly proves herself to be pretty capable because that's what's expected of a man. But she's biologically a girl. Everyone thinks she looks female, but everyone takes the fact that she's male at face value because she says she's male and dresses like a guy. They don't see boobs, so they don't question it. So then what is a man? No boobs and the right attitude? In other mangas, they'd have her periodically doing something to look horribly weak, just to remind us all that she's really a girl (and therefore weak), but thankfully not so much here. Sure, she always cries after she loses at ski jumping, but there's a psychological reason for that, not so much a gender reason for it. (Kurogi doesn't get frustrated in the same way at ice skating, for instance.)
Yeah! You can see all his efforts in taking all those thousands of research photos really paying off there!